Hello, I updated Joomla (from 3 to 4) and now I have this message in the backend, what's wrong? Where can I adjust this?

Joomla\CMS\Filesystem\Folder::files: Der Pfad ist kein Verzeichnis. Pfad: Joomla\CMS\Filesystem\Folder::files

Please help. Thank you, greetings, Monika