Cant do anything

Hi, I have nextcloud installed on my server. When I try to delete files its says Error deleting file “whatever the filename is”. When I try to upload files it says Forbidden.

When i click on the x on the notification it says Failed to perform action

Can someone please help me

Make sure you set up all your permissions correctly, particularly your data directory.
https://docs.nextcloud.com/server/12/admin_manual/installation/installation_wizard.html#setting-strong-directory-permissions