Joplin with mailbox.org

Hello,

I am using joplin on my android device an it works perfectly. Unfortunately I can’t convice joplin to synchronise via webdav with mailbox_org.

It fails with different error messages either “unknown”, “no access” or “folder not found”.

I also opened a topic at the mailbox_org board but no solution there either.
https://userforum.mailbox.org/topic/joplin-per-webdav

It seems that the same errors appear in the iOS app.

The Linux client throws the following error messages:

Error. Please check that URL, username, password, etc. are correct and that the sync target is accessible. The reported error was:
PROPFIND : Unknown error 2 (412): (Code 412)

Was anyone successful to sync yet?

Thanks and Regards