Thanks for the reply. Sure, we have apache2 on the same server, and the port 80 is taken up by it. But no matter which port I choose for Caddy, following this guide, nothing changes. Currently, my Caddyfile looks like this:
https://example-domain.com:3001 {
proxy / localhost:3000 {
websocket
transparent
}
}
i.e., I chose port 3001. Then I restart both the RC server and the caddy. Yet, caddy then fails again, with the same error that port 80 is already in use. It obviously ignores my port settings somehow.
However, if in the Caddyfile I change https://example-domain.com:3001 to http://example-domain.com:3001, and restart the caddy, it starts fine without failing and listens to port 3001. But I need SSL to be enabled. What could be the problem here?