Syncing Tasks with Thunderbird

I just have freshly installed Nextcloud on my webspace (webhosting via a hosting provider). I can access everything well via a browser / webfrontend.
Further I want to sync calendar and tasks with Thunderbird clients. One is on Windows, one on Lubuntu. The syncing of the calendar is working well in both directions. But I cant get syncing of tasks.
There is no error message in Thunderbird, nor is anything elese shown up in the category “tasks”.

I have searched in this forum and via google, to find a solution, but got none. So I ask for help here:
I want someone to tell me step for step, what I have to do, to get tasks syncing with Thunderbird.

I think I’m having the same issue, though it might be different because syncing works in some directions for me. If I create a task in the web interface, it syncs to Thunderbird fine. If I create one in Thunderbird, it shows up in the web interface, but not another synced Thunderbird.

I’m using Nextcloud 12.0.3, Nextcloud Tasks 0.9.5, Thunderbird 52.3.0, and Lightning 5.4.3. I’ve also checked Thunderbird’s calendar debug logs and the server logs, neither of which helped much.

i take this thread to expose my problem, which has certain similarities with yours
just exported my 1192 contacts from Apple’s Adressbook to the ugly interface of Thunderbird
and just synced theses 1192 Thunderbird’s contacts with my new Nextcloud account
problem : only 393 contacts appear in Nextcloud
where are the 799 others ?

after one night, all the contacts seem to be there…
maybe it needed some time

For me syncing of Tasks with Thunderbird works.
But I have Thunderbird 52.3.0 and Nextcloud 12.0.2.
In Thunderbird you can open the Error console (Tools->Developer Tools->Error Console). In the log category “Net” you will see the HTTP request and response headers. Maybe that helps debugging the problem…