Just to double-check, first use the web interface to see that indeed, your calendar is still live and accessible.
I'm also assuming that, as you said, you have the appropriate version of Lightning (no problem if it says, in the description "an
integrated calendar for Thunderbird") and the latest version of "Provider for Google Calendar" (v. 3.3).
Then, back to Thunderbird / Lightning, Google had "improved" their sing-in dialog box about 1 week ago. Don't ask me why, but it didn't change anything for one of my gmail accounts... and disconnected the other one. Go figure! The solution is to remove the saved password from Thunderbird and to force Thunderbird to ask it again.
Here is how to do it.
0. Do a copy of your profile, just in case. Better be safe than sorry!
1. First, if you have any special configuration (name, colour of each of your Google calendars), please note them as they may disappear in the process.
2. Press ALT to display the menu bar, then Tools –> Options. Select "Security" and click on "Registered passwords"
3. In that window, enter an appropriate search string (ex.:
myaccount@gmail.com).
Amongst the connection lines, search for the following (I think) :
oauth:myaccount@gmail.com (Google Calendar OAuth Token)
Delete it.
(Worst case scenario, delete anything that is not labeled imap and smtp; but you might have also to reenter your password for Gmail too).
4. Quit Thunderbird and restart.
5. Either one of these two things will happen (and I have seen both). You will either see that:
– you will simply need to reenter your password and all Google calendars will be accessible, or,
– all your Google calendars will disappear; you will have to reconnect to them one by one. Obviously, as they are on Google, all the information will reappear within a few minutes.
