I wanted to post one further workaround. This is thanks to a co worker of mine.
He tells me that when using the gnome shell and evolution, he *did not* use the online accounts at first. Instead, he first manually configured his IMAP email account (his personal email account) as he always did within evolution. He then went into online accounts and configured his ews account through gnome shell and everything worked :)
I wanted to post one further workaround. This is thanks to a co worker of mine.
He tells me that when using the gnome shell and evolution, he *did not* use the online accounts at first. Instead, he first manually configured his IMAP email account (his personal email account) as he always did within evolution. He then went into online accounts and configured his ews account through gnome shell and everything worked :)