502 error no access

Good morning,
I have installed the latest version of Nextcloud on my Nas (Synology Docker). Locally I also have access to the instance and everything is working fine.
But as soon as I want to access via my subdomain (https), I get a 502 error. As far as I know the certificate is also up to date.
An error occurred while processing this request.
Can anyone help me further. In the config I have stored my subdomain.
Attached is my reverse proxy rule.

Bildschirmfoto 2022-03-06 um 08.47.25

Nobody any idea? How can i fix it?