Error using Caddy/ reverse proxy

[TheDreadPirate]

I'm not too familiar with Caddy. It really should be as simple as typing in http://jellyfin.domain.tld (no port 8099) in your browser, and having caddy proxy to Jellyfin port 8099.

I found these Caddy forum posts that are very similar to yours.

https://caddy.community/t/reverse-proxy-...reen/13303
https://caddy.community/t/blank-page-loa...roxy/15176

Also, since you are using caddy, you should turn OFF port forwarding on port 8099 so that your Jellyfin server is not directly exposed to the Internet.