bind address already in use

[robertkwild]

hi all,

trying to do a reverse proxy on my ubuntu but i get this error


caddy reverse-proxy --from host.domain.com --to 127.0.0.1:8096
2026/08/14 20:13:15.658 WARN admin admin endpoint disabled
2026/08/14 20:13:15.658 INFO http.auto_https server is listening only on the HTTPS port but has no TLS connection policies; adding one to enable TLS {"server_name": "proxy", "https_port": 443}
2026/08/14 20:13:15.658 INFO http.auto_https enabling automatic HTTP->HTTPS redirects {"server_name": "proxy"}
2026/08/14 20:13:15.658 INFO tls.cache.maintenance started background certificate maintenance {"cache": "0xdc1a859f680"}
2026/08/14 20:13:15.658 INFO http enabling HTTP/3 listener {"addr": ":443"}
2026/08/14 20:13:15.658 INFO http.log server running {"name": "proxy", "protocols": ["h1", "h2", "h3"]}
2026/08/14 20:13:15.658 INFO tls.cache.maintenance stopped background certificate maintenance {"cache": "0xdc1a859f680"}
2026/08/14 20:13:15.658 INFO http servers shutting down with eternal grace period
Error: loading new config: http app module: start: listening on :80: listen tcp :80: bind: address already in use


thanks,
rob

[TheDreadPirate]

Code:

sudo ss -tulpn | grep :80

What is the output of that command?

[robertkwild]

ss -tulpn | grep :80
tcp LISTEN 0 512 0.0.0.0:8096 0.0.0.0:* users("jellyfin",pid=1202,fd=480))
tcp LISTEN 0 4096 *:80 *:* users("caddy",pid=1197,fd=6))

and when i open firefox localhost i do get the caddy welcome page

[TheDreadPirate]

Did you start caddy as a reverse proxy for another app? If you have multiple apps that will be behind caddy you should be using caddyfiles to configure caddy.

https://jellyfin.org/docs/general/post-i...oxy/caddy/

[robertkwild]

thanks, where do i save the file to what path?

i see file /etc/caddy/Caddyfile

do i enter this in that file, in between the 80 {}

example.com

redir /jellyfin /jellyfin/
reverse_proxy /jellyfin/* 127.0.0.1:8096

[TheDreadPirate]

Do you want to do a subpath? Generally I don't recommend doing that. I recommend subdomains over subpaths since subpaths require additional configuration in Jellyfin.

But yes, that is what you would put in the 80 block. With your actual domain name. Preferably you would redirect all port 80 connections to the 443 block for a secure connection.

[robertkwild]

interestingly when i put the subpath command lines inbetween the 80 curly brackets it didnt work as when i did a "systemctl restart jellyfin" i got an error but when i put the command underneath ie appended to the last line of the file it worked, i can now access my jellyfin server via the wan using the domain and subpath ie "domain.com/jellyfin"

obvs i also went on the gui and added it there aswell under admin > networking > base url

[TheDreadPirate]

That may be correct, as I am not a caddy user I am not familiar with how caddyfiles are written and their documentation is kind of ambiguous.

Anyway, just make sure that you properly setup https in caddy. Don't use http over WAN due to the risk of your password and access token getting exposed.

[robertkwild]

on my router, im only port forwarding 443 anyway so i def know its working, plus when i type in on my mobile lets say with no https:// ie

domain.com/jellyfin

it auto redirects it to https:// infront of it so all good

thanks TheDreadPirate