I have noticed that for a couple months now my Thunderbird randomly stops syncing Calendars until I restart it. Changes that I've made to calendars elsewhere are not shown in Thunderbird, even if I press the Synchronize button. But when I restart TB, the calendar starts syncing correctly again. I am using the extension "Provider for Google Calendar" and three types of calendars: one local, around 10 NextCloud CalDAV calendars and around 10 Google calendars. The problem affects at least the Google calendars. This is a laptop that is moving around and so the network connection goes down regularly. In addition, some of the calendars are behind VPN so they go offline often. The laptop is also put to sleep mode regularly. I think the problem might be triggered by these events. I think this is a bug somewhere. My question is, is there some way I could I help diagnose this problem when it happens the next time? The activity manager list was empty at the time of the problem.