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 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.