Configuring DAVdroid or NextCloud ? Good old time

Hi all,
I used OwnCloud for a long time with synked calendars, addressbooks, files… between a computer, a phone ( I’m a happy owner of a Fairphone 1 ), several accounts on several sites… Good old time where thinks were easy…

I’m just installing NextCloud 14.0.0 on my little shared hosting in order to test it and have an instance for a little npo. I’ve upgraded php to 7.2
After a long time of floundering ( I can’t use urls in https, only http for synking… why ? ), I’ve been able to get Thunderbird synking calendars, tasks and addresses.

But I still get troubles on the mobile.

I upgraded DAVdroid to 1.9.2 and got nothing.

So I downgraded to and back to

Now, the tasks (with OpenTask) seem synked. But I can’t synk calendars.

I can see the list of calendars loaded in the Calendar app, but no event appears.
In the “Synchronization” panel of the parameters “Agenda” (calendars) remain empty when “Tâches” (Task ) need a few seconds to synk and get a synk date and time.

Has somebody some knowledge of this kind of problem ? Is Nextcloud 14 interface so different than the old OwnCloud I used ?

If there is some experiment I can do, if you need more information. I would do all what I can to give you hints… to get a solution.

Many thanks in advance.

Sounds like the syncing is working, if things show up in OpenTasks etc.

I use Simple Calendar: and if I enable CalDAV in its settings everything works great.

Thanks Kristian,
I just loaded Simple Calendar, but the problem is still the same.

An example of the problem :
When I try to sync the addressbooks, I get the list of the calendars. Let us say that the link given for the addressbook is
I enter it in DAVdroid and get the list of my calendars.

An other hint, maybee. In the calendars app, I can create an event, and chose one of my calendars I subscribed. But ther is no sync with the server.

Is it a way to have a look on the content returned by Nextcloud ?
In the browser, when I ask the url I get the message “This is the WebDAV interface. It can only be accessed by WebDAV clients such as the Nextcloud desktop sync client.” Which header must be sent, let us say with curl, to get an answer.