"earlier this week thunderbird asked me log in to google, not sure why i needed to do this because it was fine the day before." Because Google decided your authentication needed updating. They do it often. If you have disallowed Liughtning in the app on the gmail account or entered incorrect information then the sync process may well stop. You should also ensure you have enabled CALDAV in the gmail account settings. here https://www.google.com/calendar/syncselect

Also check that you have disabled in the config editor the preference network.http.spdy.enabled.http2draft by setting it to False

I have checked these setting, in the syncselect panel on google, the calendar I want to sync is greyed out but ticked. The config setting is set to false in thunderbird. No change. In fact today I notice that events that I wrote on friday in my calendar that synced over to google and subsequently to my iphone have now disappeared from my thunderbird/lightning calendar ! This makes no sense at all. I wrote some test events thursday and friday and they remained on my calendar and synced to google, still nothing synced back from the last few years or future events. The test events I wrote were there yesterday and then this morning when I open thunderbird they are no longer in the calendar, yet they ARE on my google calendar.

I am also having problems similar to this. My Lightning calendar shows all my events synced from Google then, for no reason it drops them, I look in Google Calendar and they are all there. I edit and re-save the events in Google Calendar and then force a sync in Lightning. The events re-appear in Lightning, but then disappear again a day or two later??!! Driving me mental!!!

at the end of October I installed older versions of provider and lightening and everything was restored to the way it should be. It has worked perfectly for the last few weeks. BUT THEN WTF today I was asked for my google password again !!!! SERIOUSLY !!! not my calendar has disappeared AGAIN.

I'm trying to run a business here !!! Google still has my calendar and my phone and PC are synced fine, but something has been changed AGAIN without the relevant plugins being checked thoroughly. Lightening seems to be the same and provider has not updated either as I have those options turned off. SO has anyone else had this happen today? it was working perfectly until about an hour ago !! I left the office for an hour, came back and the password request was on the screen and my calendar has vanished.

This is insane that this should happen to such a popular piece of software.

bigdaymartin. I just spent the last 90 min trying to REFIX this, to no avail.

it won't take the password. I'm pulling my hair.

I struggled for a couple of hours yesterday, in the end I thought what the hell i'll try the latest version to see if they made any changes. I deleted lightening and provider. I tried installing through the add ons page but it wouldn't work so I downloaded the latest version of lightening and provider. installed 'from file' lightening first then provider, making sure auto updates were off. I went in to lightening calendar and set up a new calendar to link to google and it asked for my google password, THIS time it wasn't a little box appearing asking fro the password, it was a separate box popping up with google branding asking for the details and when I entered it logged in fine, it took a while to sync the calendar but IT WORKED!!! Everything is back to normal. I guess provider has had changes made and possible any changes made by google have been overcome. so as of now it is working on my mac. I am skeptical that it may disappear again at the next update but it seems to be ok now.

For any one else reading this, I deleted the accounts from Thunderbird/Lightning, changed my options in Google Calendar from share to not share and then back again. Re-added the accounts and then I too, got the Google approval box after which everything seemed to work fine. Must be another Google control issue. GOOGLE is the new BIG BROTHER.

I deleted both Lightning and Provider modules. I changed the share to not share and then back in Google. I installed Lightning. Restarted TB. I installed Provider 1.0.2. (newest version). Restarted TB. I got the dialog with Google request for password and authorisation to share. I did not erase the calendars in Lightening, but they were not checked. I checked the boxes and they synch instantly.

So I guess this is the recipe to follow whenever Google Calendar messes up.