Hi @arandorap, from what I’m understanding you want to run a HTTPS site publically on port 8033 and have LetsEncrypt issue the ACME challenge to that port.
This isn’t possible. LetsEncrypt must validate your website on port 80 or 443. Alternately, you can use DNS to validate ownership.
Alternately, if you have port 443 available at the edge of your network, but must pass it to port 8033 on your Caddy host inside the network, the Caddy equivalents that you’re looking for are the -http-port [number] and -https-port [number] flags, and this should work as long as you’ve forwarded traffic from [your-website]:443 → [caddy-host]:8033 as @matt mentioned.