After many attempts i have found this solution.
Run Powershell as administrator and type this:
Set-SmbClientConfiguration -EnableInsecureGuestLogons $true -Force
this will allow insecure guest logins which were deactivated with the past windows updates
https://learn.microsoft.com/de-de/windows-server/storage/file-server/enable-insecure-guest-logons-smb2-and-smb3?tabs=powershell