Invites can only be accepted into local calendars

User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.3) Gecko/20100401 Firefox/3.6.3 (.NET CLR 3.5.30729)
Build Identifier: Lightning 1.0b1

Use case:
I set up Lightning to be integrated with Google Calendar. I have two calendars in Google, but have none locally in Thunderbird. I expect to be able to respond to event invitation letters by accepting, declining, etc. and saving said events to one of my calendars (provided by Google).

The problem:
When I receive an event invitation letter, the toolbar showing the Accept, Decline, etc. buttons is missing (it's there if I have a local calendar). This prevents me from sending out automatic responses and saving the event to one of my calendars.

Reproducible: Always

Steps to Reproduce:
1. Set up a Google Calendar and integrate the service with Lightning.
2. Delete your local calendars.
3. Receive an event invitation letter.
Actual Results:
The Accept, etc. buttons are not shown for the event.

Expected Results:
I would expect the Accept, etc. buttons to be shown, as normal.

The issue can be worked around by dragging the letter to the Today pane, but in this case Lightning sends out invitations to this event to the other attendees! The Notify attendees checkbox can't be unchecked. The other attendees can be manually deleted, but that's tedious work for simply accepting an invitation...

There might be a connection to the following bug: https://bugzilla.mozilla.org/show_bug.cgi?id=543471

Are you using the Provider for Google Calendar? If yes: please read <https://addons.mozilla.org/en-US/thunderbird/addon/4631/#release-notes>.

Thank you. I am indeed using Provider and I apparently I missed the comment about accepting invitations. My bad.

Sorry if this has been answered long ago, but I feel like I have the same issue still, and the above answer didn't really address the underlying problem.

It seems like the main issue is that Provider for Google Calendar / Lightning can't accept an Outlook/.ics invitation into anything except a Local Calendar. Is that correct and by design?

My problem is that the invitation isn't being sent to my gmail account, so having gmail automatically accept invitations doesn't help.

The invitations come into a work account (we're not allowed to use gmail for work), and I need to get them accepted into my gmail calendar (which I can use...).

Currently, I can accept an incoming invitation using Lightning/Thunderbird, but it saves it to my Local Calendar. Then, I have to copy the event into my gmail calendar (in Lightning/Thunderbird).

What I don't understand is why there's not an option, or it's not possible, to just configure Lightning to accept the invitation directly into the gmail calendar?

Thanks very much.

I would second, third and fourth the above comments.

THIS ISSUE STOP LIGHTENING BEING A USEFUL SOLUT|ION FOR ME

We have company calendar's on google
I "see" all those I wish in TB/Lightning - saves me logging into Google
I can accept invites from company employees - event shows in google calendar
However when I accept an invite it's added to the local calendar so

1) The event is not visible to other employees
2) My diary is split over two calendars

point 1 and 2 MAKE THE WHOLE THING POINTLESS

I'm sorry this is bugging you, but this is really an issue that should be fixed at Google first, otherwise its a fight against windmills. I've referenced the google issue many times before.

I think I can help.

First, create a new CalDAV Calendar in Lightning that points to your Google calendar using the following when prompted:

https://www.google.com/calendar/dav/ [ your Google Calendar ID ] /events

Where [ your Google Calendar ID ] occurs above, use your Gmail login name. Continue through the setup, and you'll eventually be prompted for your password etc.

Now, your Google Calendar should show-up in Lightning. To accept the ics file, YOU MUST have Thunderbird Email client set to view attachments INLINE. If you do so, the Accept Decline ect buttons will show when you open the email. ALSO, I've found that you must actually open the email, not just look at it in the preview window. Hope this helps - it's working for me.

Dean
Thanks for the reply - tried your suggestion but something it not working correctly.
1) THe calendar, in TB had warning icon, tip says calendar is momentarilty unavailable
2) The new dav calendar is constantly popping up reminder boxes for ALL items in the calendar. I dismiss all and then they re-appear
3) A warning, saying modification failed, is also appearing when trying to dismiss the reminders.

On the positive side appointemtns appeared in TB and new events were created. I didn't get around to teting the original problem until I can get the calendar working properly

any thoughts

thanks
Malcolm

(In reply to comment #7)
> I think I can help.
>
> First, create a new CalDAV Calendar in Lightning that points to your Google
> calendar using the following when prompted:
>
> https://www.google.com/calendar/dav/ [ your Google Calendar ID ] /events
>
> Where [ your Google Calendar ID ] occurs above, use your Gmail login name.
> Continue through the setup, and you'll eventually be prompted for your
> password etc.
>
> Now, your Google Calendar should show-up in Lightning. To accept the ics
> file, YOU MUST have Thunderbird Email client set to view attachments INLINE.
> If you do so, the Accept Decline ect buttons will show when you open the
> email. ALSO, I've found that you must actually open the email, not just
> look at it in the preview window. Hope this helps - it's working for me.

Just upgraded to Thunderbird 5 from 3 and to lightning 1.0b4. We use CommunigatePro for our email server which has a CalDAV calender. Everything worked great in older version, could accept invitations, saved properly to our calendar. Now when I hit the accept button, it just goes away. If I add a local calendar, it pops up the calendar selection and if I select local, it works, but if I select my network calendar, nothing happens... I can drag the invitation into the today panel and that works....

(In reply to comment #6)
> I'm sorry this is bugging you, but this is really an issue that should be
> fixed at Google first, otherwise its a fight against windmills. I've
> referenced the google issue many times before.

Can you reference it again for tose who a new to this - please

http://code.google.com/a/google.com/p/apps-api-issues/issues/detail?id=1079

I have a similar problem, and it has nothing to do with google.

Thunderbird 7.0.1 with Lightning 1.0b7 on Win7 x32, CalDAV or iCal calendar on Zimbra 6.0.6.

Steps to reproduce *my* problem:
1. Create a (second) local calendar in lightning
2a. Create a CalDAV calendar in lightning using http://my.server.tld/dav/USER/CalendarName OR
2b. Create an iCal calendar in lightning using http://my.server.tld/home/USER/CalendarName
3. Let an Outlook user send you an invite

Actual results with iCal calendar (2b):
In both the preview window and when I open the mail as new window or tab, it is formatted like lightning formats invitation mails, with a blue bar on top saying "this mail contains a calendar event", but without the buttons for accepting/declining. I cannot do anything with this invitation except view it in the mail. I could also drag its attachment (*.ics) to the calendar/tasks pane; this will create a "new calendar event" dialog, pre-filled with the actual event data, but this of couse won't let the organizer know that I want to accept/decline.

Actual results with CalDAV calendar (2a):
This time, the accept/decline buttons appear in the blue list, but when I click accept, I get a dialog saying "select calendar". Unfortunately, this dialog ONLY LISTS MY TWO LOCAL CALENDARS, which doesn't help me because I need it in the remote calendar. Again, I could always drag the .ics attachment to the sidebar, creating a new event, making myself the organizer.

Expected results with both iCal and CalDAV:
I click accept, a dialog lets me select any of my (non-readonly) calendars, including CalDAV and iCal ones, asking me whether I want to send a notification mail, event is then added to the chosen calendar.

I'm on latest EarlyBird 22.0a2 with latest nightly Lightning 2.4a2.

I have attachments inline, but where the "accept, decline" buttons used to be i now get a message: "No writable calendars are configured for invitations, please check the calendar properties"

"Read only" is not enabled in the calendar properties and i can add events manually just fine. perfectly writable.

This is still an issue after such a long time! Can only accept invites to local calendar and cut/paste to Google calendar will re-invite (aka spam!) all attendees. Thunderbird 17.0.6, Lightning 1.9.1, Provider for Google calendar 0.18, Ubuntu 13.04, 64 bits.

Using this method to add a Google calendar solved the problem for me:&#013;http://blog.mozilla.org/calendar/2013/09/google-is-changing-the-location-url-of-their-caldav-calendars/&#013;&#013;ThunderBird 24, Lightning 2.6.1 provider for Google Calendar 0.25

Thought I was hitting a new Lightning bug. Then I read this wiki which showed me how to enable Email notifications for Google Calendars. https://wiki.mozilla.org/Calendar:Configuring_Lightning

I had no idea I had to do this to be able to accept Google invitations.

tl;dr: set calendar.google.enableEmailInvitations to true in the Config Editor.

Good url:

http://blog.mozilla.org/calendar/2013/09/google-is-changing-the-location-url-of-their-caldav-calendars/

+1 this happens for me. The only calendars I have are google calendars.

I have been annoyed with this for a long time. Didn't realize that it went back that far. :)

In reading this just now I learned about the config-editor setting to change ( calendar.google.enableEmailInvitations ). Mine was false, I have now set it to TRUE but I am still not getting my Google calendars to show up when accepting invites.

T-bird 24.2, Lightning 2.6.4, using Google Provider .24.

However, my situation may be a bit different: when I get an invite, the 'Accept', 'Decline', 'Tentative' buttons all show up OK in the email header area. When I click on the Accept button, the pop-up window listing the calendars only shows some of them, none of which are my Google calendars which I would like to be using. However, if I go to the calendar itself, I will see that same invitation show up in the proper calendar as a tentative event (ghosted color, dashed border). If I then open that event and change my status to 'Will attend', the event properly stays on that calendar and I have now 'accepted' it.

Also very curious is that there is another Google calendar that I subscribe to (not mine, but a co-workers), and THAT calendar DOES show up on the pick-list when I hit 'accept' from the email interface. Very strange.

(In reply to justinclose from comment #19)

> However, my situation may be a bit different: when I get an invite, the
> 'Accept', 'Decline', 'Tentative' buttons all show up OK in the email header
> area. When I click on the Accept button, the pop-up window listing the
> calendars only shows some of them, none of which are my Google calendars
> which I would like to be using. However, if I go to the calendar itself, I
> will see that same invitation show up in the proper calendar as a tentative
> event (ghosted color, dashed border). If I then open that event and change
> my status to 'Will attend', the event properly stays on that calendar and I
> have now 'accepted' it.

Uh, just figured out something (10 minutes later): I got this working for one Google calendar by opening the calendar properties screen and setting an email address for that calendar. This setting was new on this screen after having turned ON the flag for calendar.google.enableEmailInvitations in the config editor. Once I did that, at least for one invitation I had, I was now able to pick that calendar from the pop-up window. HOWEVER, I have a second calendar defined on that same account and that one was NOT shown in the pop-up.

+1 here with the "No writable calendars are configured for..." problem. I only use Google calendars, I have two. I am displaying attachments inline and have checked the setting of calendar.google.enableEmailInvitations and it was false, but even after setting to true and restarting nothing changed. I don't get the drop-down box allowing me to specify which email address each calendar is associated to.

Thanks for your work.

G.

I'm seeing the same issue. Some invitations display the message "No writable calendars are configured for invitations, please check calendar properties." however if I wait a few seconds I can still accept the invitation using the invitations link that appears in the status bar.

I'm using Google calendars via the provider for Google calendar version 0.25.

Had he same problem.. link from above fixed it for me...

https://wiki.mozilla.org/Calendar:Configuring_Lightning

I have the same problem - message "No writtable calendars are configured...." although I have done what reccomended mskuse, the calendar.google.enableEmailInvitations setting is set to TRUE.
When I open the message vcf, I see the error window and no Buttons for accept or similar.
All on Sea Monkey with Lightning 3.01b. I am able to synchronize the google calendar to SM calendar in both directions without problems.

A small addition-I have tried to create new local calendar and in such case I see the buttons and I can accept the invitation, but the event stays in the local calendar, not in the google one.

Unfortunately, after updating to SM 2.26b and Lightning 3.1b. The situation is still unchanged, not possible to accept the invitation to google calendar, only into local as above described. Unfortunately in Addons manager the setting options freezing the SM, but this could be due to beta state of both SWs.

I also have this problem, running RHEL 6 with TB 24.4.0 Lightning 2.6.4, and Provider 0.25.

I set the calendar.google.enableEmailInvitations to true. Inline attachments are enabled. No accept/decline buttons are available. I also can't import an old local calendar with some of these events. Could it be the event type that's causing the problem?

Same problem, Fedora 19, TB 24.4.0, Lightning 2.6.4, calendar.google.enableEmailInvitations=true, mail.inline_attachments=true.

Message displayed in reader is "No writable calendars are configured for invitations, please check the calendar properties."

I have verified a full round trip writable google calendar by adding an event to the TB calendar then checking on the google website, deleting the event there and then resyncing on TB.

There must be another rouge/uninitialzed condition in the check.

an additional observation... I can now accept invites and they appear (temporarily) on my event calendar... however, within a minute or two they disappear... the only way to make they stick is to open the even immediately after accepting it and accepting the invite again (since it is still showing I will confirm later). The other alternative is to log into gmail web interface and accept it there.

Same issue here: Windows 7 64, TB 24.5.0, Provider for Google Calendar 0.25, Lightning 2.6.4

Hey Guys,

I was able to overcome this by double clicking the Google calendar I set up and changing the email setting from "none" to the email address I wished to have linked to the calendar. Pretty frustrating, but I hope this helps.

I'm having an issue with 3.5a1 Lightning on the current nightly 64-bit builds where it tells me that there are no calendars configured to accept invitations and it didn't used to do that. I have the 0.34pre Google Calendar Provider too.

Try using the CalDev URL for your calendar. Instead of using the iCal link that Google itself provides, use a URL like this: https://<email address hidden>/events

This will fix your problem.

The Google calendar provider won't accept the URL for me when I try to user a link with the format above. It gives an error message and some form of stack trace.

If you want to access Google Calendar by using the built-in CalDAV provider instead of using the Provider for Google Calendar extension you need to choose On the network > CalDAV when creating the calendar.

Is there any pros/cons to using the native CalDAV support instead of the Provider for Google Calendar extension?

Setting calendar.google.enableEmailInvitations to true fixed it, but why isn't this the default?

(In reply to Matt from comment #31)
> Hey Guys,
>
> I was able to overcome this by double clicking the Google calendar I set up
> and changing the email setting from "none" to the email address I wished to
> have linked to the calendar. Pretty frustrating, but I hope this helps.

This was what finally fixed it for me! Setting "calendar.google.enableEmailInvitations" to "TRUE" was also required!

Setting calendar.google.enableEmailInvitations to true did NOT fix it for me. I do have one writable calendar from Google.

Please provide a fix, Mozilla.

Indeed strange. This setting also solved my problem, but I don't understand why this option is set on false at default.
I guess it can conflict if you got multiple calendars (like a local 'home' calendar and a second Gmail calendar)?

Furthermore, the other person don't get a confirmation (like: Accepted/'coming' or Denied/'canceled') when I accept the Google calendar invite. Why?

See comment 31 (Hey Guys,

I was able to overcome this by double clicking the Google calendar I set up and changing the email setting from "none" to the email address I wished to have linked to the calendar. Pretty frustrating, but I hope this helps.): this worked for me.

After I set calendar.google.enableEmailInvitations to true, that is (don't know if this is neccessary)

jan

I have the same issue setting up CalDAV from Kerio.

This issue was not present in Lightening 3.3.3. Only after updating this morning did it occur. I can save events to local calendar. Previously everything worked fine.

Here is the precise behavior.

1) Select "Accept" on the invitation.
2) Select the calDAV calendar in the "Select Calendar" Menu.
3) Unselect and reselect the invitation email.
4) The "Accept" menu is still visible and nothing has been added to my Calendar.

If I select the default "Home" Calendar, everything works fine. The invitation acceptance is sent and the creator of the event does get the confirmation.

I have the following settings in my calDAV calendar:

1) Correct location string.
2) Correct E-Mail.
3) Refresh ever minute.
4) Read-only off.
5) Show reminders on.
6) Offline support on.

Hello,

I searched now many hours in the internet and your forums but it seems that this Problem isn't solved yet:

No writable calendars are configured for invitations with Provider for Google Calendar.

My Thunderbird version is 38.3.0 and Provider for Google Calendar 1.0.4.

I set calendar.google.enableEmailInvitations;true but it didn't help. I also tried with ...@gmail.com and ...@googlemail.com. Calendar works fine, it synchronizes, I see all entries etc. But I can't accept invitations ALTHOUGH it should have write access.

What can I do? Isn't there a solution for this?

Thank you!
Daniel

Hi,

This worked for me:

1. In your favourite browser, look at your google calendars in each of your google accounts. Ensure that if you have multiple Google accounts and/or multiple Google calendars, you are clear on which calendars are associated with which Google accounts and which email addresses. Make a note!

2. In Thunderbird, completely delete any Google calendars. (You'll be re-adding them later).

3. In Thunderbird's View menu: Set Display Attachments Inline and set Message Body As to Original HTML.

3. Tools / Options / Advanced Tab / Config Editor: Set calendar.google.enableEmailInvitations to true and ensure that calendar.google.sendEventNotifications is set to true. Restart Thunderbird.

4. In Thunderbird, recreate each your calendars (and tasks, if desired) using these settings: "On the Network", "Google" (not CalDAV); enter the correct email address corresponding to each calendar; in the Google pop-up, ALLOW Lightning to Manage your calendars and tasks; select the corresponding calendars and tasks you wish to subscribe to, (that are associated with the email address you entered).

5. In the Calendar tab, for each calendar, select properties and check/set the correct email address corresponding to that calendar. (If you can't find the option to do this, restart Thunderbird first).

6. Restart Thunderbird.

Test it (I used two different Google Calendars / accounts / emails addresses within Thunderbird to do this):

7. Create a Calendar entry in some other account and invite your google calendar self. In Thunderbird, within the received email, click Accept. Then, go to the calendar, hit Synchronize on the top left. Check by opening the new entry. Check, in the account that originated the calendar entry, that the invitation was accepted.

8 Create a Calendar entry in a Google calendar within Thunderbird and invite yourself (or someone else) at another email address. Hit Synchronize on the top left. Go to the destination email account or calendar and accept the invitation. Go back to the Thunderbird calendar, hit Synchronize, and ensure that the invitation was accepted.

Good luck!

Newbie John.

(In reply to mskuse from comment #23)
> Had he same problem.. link from above fixed it for me...
>
> https://wiki.mozilla.org/Calendar:Configuring_Lightning

Thanks that helped.

BUT, it would be really great if one could configure multiple email accounts for one calendar for event acceptance.

The current Thunderbird build (38.7.2) with integrated Lightning shows me the accept/decline buttons which also work for saving an event to a CalDAV calendar (not Google) but it does not send a notification to the sender.
This works only with local calendars. Why and how can I make it work to send the status back to the sender if the event will be saved to a CalDAV calendar?

Hello All,

I have the same issue since TB 45.0 - I am using several calendars: Exchange, Google, and default TB.
If an event invitation arrives (from Exchange account), I have buttons to Accept, Decline, etc, but event is saves under default calendar, not to the Exchange one.

I'd like to save events to Exchange calendar by default, or at least to choose which calendar the invitation is going to be applied.

Is there a workaround for this ?

Thanks a lot, Rudolf

Thanks for confirming this. I found the information about the email invitations setting and was about to try it, when I found this bug report.

(In reply to Rudo from comment #46)
> Hello All,
>
> I have the same issue since TB 45.0 - I am using several calendars:
> Exchange, Google, and default TB.
> If an event invitation arrives (from Exchange account), I have buttons to
> Accept, Decline, etc, but event is saves under default calendar, not to the
> Exchange one.
>
> I'd like to save events to Exchange calendar by default, or at least to
> choose which calendar the invitation is going to be applied.
>
> Is there a workaround for this ?
>
> Thanks a lot, Rudolf

I'm in the same boat except I'm dealing only with a local calendar and a Google Calendar.

This seems to work for me:

Adding Calendar Tab:
Ctrl+Shift+C
OR
Events and Tasks menu, then click on Calendar

Making Google the Default Calendar:
Once Thunderbird starts -> Go to the Calendar tab and Right Click on the Google Calendar which you want the events to be processed by
Click on Properties
Select the Email -(gmail in this case – the calendar you want to make as default for accepting invitations)
OK-> Close

Hope this helps

(In reply to doberkid from comment #48)
> This seems to work for me:
>
> Adding Calendar Tab:
> Ctrl+Shift+C
> OR
> Events and Tasks menu, then click on Calendar
>
> Making Google the Default Calendar:
> Once Thunderbird starts -> Go to the Calendar tab and Right Click on the
> Google Calendar which you want the events to be processed by
> Click on Properties
> Select the Email -(gmail in this case – the calendar you want to make as
> default for accepting invitations)
> OK-> Close
>
> Hope this helps

Thanks for the steps! Since I posted my last comment above, I did some experimentation and found the following:

If the Google Calendar I have defined in Lightning has the Gmail email address in it, for example:

https://calendar.google.com/calendar/ical/{someaddress%40gmail.com}/private-{some id}/basic.ics

I get prompted for which calendar to add event invitations to. If the Google Calendar defined has the generated calendar ID in it, for example:

https://calendar.google.com/calendar/ical/gb2nmfkrko6l9jo3generated%40group.calendar.google.com/private-47c4accf8a7af8d30cdf6a9bacb123def456/basic.ics

I don't get prompted and the event invitation gets added to the default calendar.

I would prefer to keep my local calendar as the default and be prompted to choose a calendar each time I get an event invitation.

The problem is not confined to the google calendar. When accepting email invitations and using caldav calendars, the user is NOT presented with a selection dialog for the calendar, instead the event is created in the local calendar an CANNOT BE MOVED. There is no selection in the event.

So--had the same problem and here's how i solved it worked it out.

follow these directions to download plugins and create network google calendars for all of your calendars (based on your emails). So i have <email address hidden> and a <email address hidden> emails where those same emails are connected to google for calendars (and I'm not using gsuite) https://www.techrepublic.com/article/how-to-add-a-readwrite-google-calendar-to-thunderbirds-lightning/

THEN, create new local calendars for each email you have that are the same emails as the google calendar emails.

When you then receive invitations to those emails, you can accept invitations and they will go into your local lightning calendars but they will also sync with your google calendars. I have my google cals in lightning checked to see all events prior to this change, but new events don't require it.

whew!

(In reply to todd from comment #51)
> So--had the same problem and here's how i solved it worked it out.
>
>
> follow these directions to download plugins and create network google
> calendars for all of your calendars (based on your emails). So i have
> <email address hidden> and a <email address hidden> emails where those same emails are
> connected to google for calendars (and I'm not using gsuite)
> https://www.techrepublic.com/article/how-to-add-a-readwrite-google-calendar-
> to-thunderbirds-lightning/
>
> THEN, create new local calendars for each email you have that are the same
> emails as the google calendar emails.
>
> When you then receive invitations to those emails, you can accept
> invitations and they will go into your local lightning calendars but they
> will also sync with your google calendars. I have my google cals in
> lightning checked to see all events prior to this change, but new events
> don't require it.
>
> whew!

Thanks for that info!

Well, almost. The above description works when receiving calendar events from a google calendar. When i receive events from Outlook they save locally and are not synced to my google cal. I haven't debugged why.

I think I am getting invitations mostly from outlook-users. My current workaround for this bug looks like this:

1. have a local calendar, so I can accept an invitation and the event is automatically saved in that calendar
2. go that date (need to check anyway, if I really have free time or not)
3. copy event and paste it to my google-calendar (thunderbird prompts me to ask, which calendar I want to save it to)

As it is simply a matter of copying and pasting the event from one calendar to the other I do wonder, if it wouldn't be quite easy to fix this bug? (I'd like to tell everyone in my company to use thunderbird, but if people ask me, if it handles invitations well I have to say: well, ergh, no it doesn't.)

uhoh, maybe that is not a good workaround, as I had suggested. It seems to send out invitations to others, even though I'd specifically clicked on "paste without sending" or similar.. (?).

I moved to Thunderbird 60ish and I now have this problem too.
To be honest I don't understand what changed since it was usually prompting me with a dialog asking me in which calendar I wanted to add the event. Now it just say that no calendar are suitable for the invited email.

There is no email selection in Google Provider calendars, I don't even know if with the current OAuth2 authentication methods we can use caldav anymore.

I found this in about:config `calendar.google.enableEmailInvitations`, you can set it to true. Then restart Thunderbird then you will be able to select an email for each primary calendar !

See https://infraadvisory.wordpress.com/2015/12/01/make-google-calendar-default-in-thunderbird/

This about:config setting doesn't solve it for me.

For me, Rémys solution has worked perfectly, thanks for sharing! @Andreas: did you follow all the steps described, restarting TB at the very end?)

Created attachment 9042041
about-config-screenshot.png

Here is how it looks in the about:config dialog. Make sure to use the same spelling and camelcase writing.

Just for Information: There is another Bug #1520554.
I followed all the steps (including restarting, ...).
:-(

Addtional debugging info:
Debugging turned out that calItipUtils.jsm (@ line 202) did not find any writable calendars.

Currently I uninstalled Thunderbird, cleaned up any cached data and reinstalled Thunderbird. It doesn't work for me.

Do you have the add-on "Provider for Google Calendar" installed? That's probably a must (?)

Of cause ;-) I have installed:
TB 60.5.0
Lightning 6.2.5
Provider for Google Calendar 4.4.2

I found the solution.
Please, see https://bugzilla.mozilla.org/show_bug.cgi?id=1520554#c11

(In reply to Andreas from comment #65)

> I found the solution.
> Please, see https://bugzilla.mozilla.org/show_bug.cgi?id=1520554#c11

Thanks for the update!