Jellyfin's Kestrel backend rejects the h2c upgrade preface, so Caddy turned every request into a 502 while the same port answers 200 over plain HTTP/1.1 from Caddy's network. Default transport (HTTP/1.1) restores the vhost.
Jellyfin's Kestrel backend rejects the h2c upgrade preface, so Caddy turned every request into a 502 while the same port answers 200 over plain HTTP/1.1 from Caddy's network. Default transport (HTTP/1.1) restores the vhost.