Unable to connect to calendar and address book from thunderbird


I just reinstalled my system (with Debian 9), and a new Thunderbird (60.4.0)
I could not connect to the calendar using lightning or to the address book using cardav:

  • no error message for the calendar, but it remains empty.
  • unable to validate the URL/username/password in cardbook.

I finally found the solution on the mozilla support. I guess that can be interesting to share it here:


I also copy here the solution, given by Fabián Rodríguez:

"I believe this is the CalDAV known-issue, it’s a NextCloud problem. It’s been reported in this issue, there is a workaround:

Go to the config editor (Settings -> Advanced -> General -> Config Editor)
Search for network.cookie.same-site.enabled
Set it to false 

For your own security you should set it back to true once this issue is resolved.

This was also mentioned in the release notes (very bottom of https://www.thunderbird.net/en-US/thunderbird/60.0/releasenotes/ )"


(Sorry you reported the solution, but there was no way to say it :/)

Thanks a lot for reporting and your findings!

It has been a bit Rock’n’Roll lately with Nextcloud :confused: To their defense, Card and Cal are crazy protocol and there are crazy implementations on the market. In the coming weeks, we’ll update all our Nextcloud instances to 15, and this also should ease some pain.

Probème NextCloud 2.5.0
Nextcloud client 2.5.1 windows