OPDS behind Reverse Proxy issue

Hi,

I am using Ubooquity in docker on my Synology nas and today enabled reverse proxy to use it outside network. It works fine in browser.

But when i try to add opds to any of the reader it fails to connect to service (even in browser, it says "This XML file does not appear to have any style information associated with it"). If i use ip address and port it works fine.

One of the client prompt me for credentials but it never success in validating it.

Please suggest.