I've got the same problem after updating from vivid to wily.
Usually one of the wi-fi or mobile internet connections are affected. The problem arises occasionally, somtimes immediately after bootup, sometimes ater resume from sleepmode. If it's the case in the syslog appears a similar warning how described in the initial post.
Additionally this warning occures:
gnome-session[1487]: (nm-applet:1690): nm-applet-WARNING **: ModemManager is not available for modem at /org/freedesktop/ModemManager1/Modem/0
I've got the same problem after updating from vivid to wily.
Usually one of the wi-fi or mobile internet connections are affected. The problem arises occasionally, somtimes immediately after bootup, sometimes ater resume from sleepmode. If it's the case in the syslog appears a similar warning how described in the initial post. 1487]: (nm-applet:1690): nm-applet-WARNING **: ModemManager is not available for modem at /org/freedeskto p/ModemManager1 /Modem/ 0
Additionally this warning occures:
gnome-session[