Hi, All my google calendars have been working fine during the last few years, but now, I do not manage to synchronize them. I keep getting a blank popup instead of the Google login/password page... I am using Thunderbird 45.2.0 and Lightning 4.7.2 (well, icedove and iceowl under Debian) Here are the tests I have performed so far, with no success: - I have tried to unsubscribe and re-subscribe to my calendars, - I have removed the stored passwords, - I have toggled the value of calendar.network.multirealm, - I have started Thunderbird with an empty profile (removed the whole directory in $home), The only log entry I get in the console (nothing before I close the google login popup) is: Error: [calCachedCalendar] replay action failed: null, uri=https://apidata.googleusercontent.com/caldav/v2/<email>/events, result=2147500037, op=[xpconnect wrapped calIOperation] Source File: file:///usr/lib/icedove/extensions/<...>/calendar-js/calCachedCalendar.js Line: 327 But I guess this is only the result of closing the (blank) popup with no credentials. I have also configured the same calendar accounts in SeaMonkey 2.40 and it is working just fine (the credentials popup shows the google login page)... Any help would be greatly appreciated... Thanks in advance, BE