I was just auto-upgraded to Thunderbird v91.2.1. All of my Google Calendars are now disabled. When I try to enable them, Google asks for me to authenticate. After I do so, it displays the following error message: *** Error 403: rate_limit_exceeded This app has reached its sign-in rate limit for now. Google limits how quickly an app can get new users. You can try signing in again later, or ask the developer (provider-for-google-calendar@googlegroups.com) to increase this app's sign-in rate limit. If you are the developer for this app, you can request a sign-in rate limit increase. *** Someone needs to talk to our friends at Google to get the rate limit increased. Regards,