Nextcloud overview asks for password for sabre/dav and complains about database

When login into nextcloud with the nextcloud admin and open the overview panel, nextcloud asks for a passwords for sabre/dav but no password works.

After cancel it complains about several other things

How to fix this?

If you really need 4 byte chars (you can have emojis in filenames), here you are. I hope it still works but - WARNING! - this database settings may not work with other applications…

In the Nextcloud application settings in the server manager you can enable CalDAV/CardDAV for Nextcloud to get of the warnings: