Sounds like you’re using nginx proxy Manager, a web based frontend for nginx. If so, you have to edit your existing host, change to custom locations, add one with “/” as the address and the same containername and port. Then click the cogwheel in this entry to open a text box for custom rules. You can paste the following lines into there:

proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-Host $server_name;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;