I found the solution.
Please, see https://bugzilla.mozilla.org/show_bug.cgi?id=1520554#c11
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https://bugs.launchpad.net/bugs/810622
Title:
Invites can only be accepted into local calenda
Of cause ;-) I have installed:
TB 60.5.0
Lightning 6.2.5
Provider for Google Calendar 4.4.2
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https://bugs.launchpad.net/bugs/810622
Title:
Invites can only be accepted into local calend
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.
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Just for Information: There is another Bug #1520554.
I followed all the steps (including restarting, ...).
:-(
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Title:
Invites can only be accep
This about:config setting doesn't solve it for me.
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https://bugs.launchpad.net/bugs/810622
Title:
Invites can only be accepted into local calendars
To manage notifications about this b