CalDAV failed with Thunderbird 78.1.0

  • Hello,

    I have installed new Thunderbird version 78.1 on windows 10. Kopano core is version

    Now I have tried to synchronize my global/public calander via CalDAV.
    But nothing happens. No calendar entries appear in Thunderbird.

    What I have done:
    Created new network calendar in Thunderbird. Type CalDav.
    Adress: https://HOSTNAME:8443/caldav/public/CALENDAR NAME/

    First think I realised is that the new calendar implementation in Thunderbird has a field for username if I select CalDAV.

    And in the log file I find some messages “Missing authorization data”.
    Older Thunderbird versions with Lightning plugin works. No problems in creating calendars or requesting data.

    Any tipps what I could do, to get my calendars get back to work?



  • Hi,

    we’re hitting exactly the same issue with Thunderbird 78.*. Does anyone has a clue what to do to get around this?

    Thunderbird 68.* is running EOL these days, so there have to be a way to use public calendars with the actual version.


  • Same issue here with Thunderbird 78.x and Kopano core 8.7.1 (UCS).
    Personal user calendars work fine, only public calendars are not synced to thunderbird. However, strange thing is, that I can add appointments from thunderbird and they are synced to the server (can see them in the WebApp).
    Also, this issue does also occur on one of my instances. In another environment with same thunderbird and kopano versions works as expected.

    Any ideas?

  • Hi,

    we opened a ticket (KS-46162) some weeks ago. We got no answer 'till today. I just created a follow up, let’s hope to get an answer from the support.


  • To workaround this problem you can add the string variable


    in the Thunderbird config editor. A value with


    somewhere in it will solve the problem.