Puntuado con 5 de 5 estrellas

I was really annoyed - I use Thunderbird 78.7.1 for Mac and the AddOn in version 78.0.1. I use various Google calendars both privately and professionally, all of which I had integrated during the initial setup. After restarting Thunderbird, the programme no longer displayed any calendar contents, only a constantly "busy" cog was turning. Calendars were listed but had no content. In the forums mostly desperate people wanted to go back to TB 68.
My solution: deactivate "Provider for Google Calendar" in the Thunderbird AddOns (do not uninstall). There is then a prompt asking whether the calendars should all be de-registered - I cancelled this, but the whole thing was then deactivated anyway (seemed like a bug to me). Then activate the add-on again with the slide switch - the contents of the calendars are displayed again. Now restart Thunderbird completely - then everything works fine. Somehow the add-on needed a kind of restart.