I installed Thunderbird (68.2.1) and the Lightning (68.2) with Provider (68.0), when I add a new calendar (from the network) and choose google, I connect to google (after successful authentication), but no calendars populate in the box where you are supposed to select the calendar to Sync. I have tried this with several accounts and calendars. It appears to be an issue with Provider? I have disabled and re-enabled with restarts both Add-ons. I completely removed both add-ons and reinstalled - restart. No dice.