I'm running Thunderbird 78.14 (64 bit) on Ubuntu 20.04 on both a desktop & my laptop. Using Provider for Google calendar to access my Google calendar in Lightning. All worked well on the desktop & laptop for some years. Recently I noticed the laptop wasn't displaying my Google calendar. When I try to Create New Calendar, On the Network, Google Calendar it does not locate my existing Google Calendar on the "Please pick an existing session..." popup. There is no session to select. If I enter my Email address & press Next to the "Please select Calendars & task lists ..." popup it endlessly just sits there. I've tried uninstalling the Google provider addon & starting & restarting & also updating Lightning from file to no avail As I say it all works flawlessly on the desktop (& used to on the laptop too), but I cannot get the laptop (Thinkpad 131) to locate the calendar at all. Seems to be the same problem as this? :-https://support.mozilla.org/en-US/questions/1230294 But I cannot see the resolution.