CardDav and CalDav don't sync

Hey; I installed e via the easy installer on my Galaxy S8
and connect with the account manager my contact and my calendar from mailcow which don’t sync.
I was wondering if this account manager is only for e/Foundation service and I have to install Davx how I forget something ?

I force the synchro everything look fine, no error message the date of the last synchro update, but my contact and my calendar are simply not there.

What should I look

Also on S8 here. This issue have never been resolved, AFAIK. Davx and task app solved the issue for me. I sync both my gandi DAV and /e/ DAV

When you are in the add accont menu, select “WebDav Adress Book”.
You can then also check the syncing of the calendar.

Thats how it worked at least with my nextcloud.
It shouldnt be necessary to install davx5 seperatly