Nextcloud permission issue

I installed docker by following the Technodad tutorial; No worries all is perfect. Then I created a user 2 and the problems came. I have several errors and I am in a labyrinth. Here is one of the messages I meet. Some also tell me (after I have tampered with the shared folder permits) that other nextcloud users can list my folders and that I must go to 0770 permission. I tried everything and always the same result. Sometimes even I can no longer create a new folder or file.If someone could give me advice or a solution.Thx very much

Zitat

Your directory is not valid Make sure that the data directory contains a ".ocdata" file at its root.

Zitat

Your directory is readable by other users

Please change the directory permissions to 0770 mode so that its contents cannot be listed by other users.