Upload to external storage fails with forbidden


I have an nextcloud Running on my RPi4. I Would like to use the external storage in the webui. I habe previously activated it and also configured the path /Media/usb

It is also shown to me in the dashboard After plugging in the stick. I can access but i cannot upload anything to the ext storage cause i geht the error Forbidden.

I have tried to chown 777 onto the usb stick but ist still says forbidden. I also went to ncp-config and fixed the permissions but ist doesn‘t helped

Any suggestions on this???