Hello @RORZE,
welcome to the community of Nextcloud 
You started a topic in support category. Unfortunately you ignored the template and a lot of information to help you is missing. Please edit your original post and add all required details like Nextcloud version, webserver type and version, os version, related log file content. Use the support template.
Without additional information the community members cannot help you.
From the screenshot you the problem seems related to external storage. do you have this issue using local storage? if you login using credential provider you don’t use internal application password - this might be the reason why external storage doesn’t work as expected. I would recommend you test with completely fresh user who never use internal password but only login and configure external storage using AD login.
Regards,
wwe