so I’ve got Nextcloud an Mailbox running in docker each behind a proxy of nginx also docker powered. I found a tutorial about how to use oauth in Mailcow to login in Nextcloud. Followed that all the way and set everything up. When trying to access via the link now I get the following error:
error_description "The redirect URI provided is missing or does not match"
any one can help me out here? What else do I need to set up or what does cause this issue?