500 Internal Server from Nginx Proxy Manager

[itsjfarmer]

Hey all, I'm using the Nginx proxy Manager LXF script - everything seems to work fine for non SSL proxies. Have a few configured and all works perfect.

I'm trying to take in HTTPS traffic and server non-HTTPS from behind the proxy server. I've configured following a variety of guides through the UI, have a Cert from Let'sEncrypt, however when accessing via HTTPS, the browser confirms the certificate, and right after accepting, I see a 500 Internal Server Error. In the logs for Immich or OpenWebUI, I see access logs for HTTP traffic fine, but when accessing via HTTPS it doesn't seem to show anything.

I've tried 2 different services now (OpenWebUI and Immich) both do the same thing.

I've tried to look at the journalctl logs for Nginx, but I don't really see anything useful (maybe that's the wrong place to look?).

I see reloads of the Nginx config there when I make a change, but no reports of errors.

Any thoughts or tips on other places to look?