I’m running Mailcow (Dockerized) on my VPS alongside CloudPanel for website hosting.
Everything worked fine initially using reverse proxy and assigning ports like:

HTTP: 8080
HTTPS: 8444
However, after a system restart, Mailcow failed to start with the following error:

Error starting userland proxy: listen tcp4 [MyIP]:8080: bind: address already in use

Looks like both CloudPanel and Mailcow are using Nginx and conflicting on port 8080.
How can I change Mailcow’s ports to fix this?

Thanks in advance!

This is a classic port conflict between Mailcow's internal Nginx and CloudPanel's Nginx.

✅ Solution:

Edit Mailcow’s mailcow.conf file and update the following values:

HTTP_PORT=7080
HTTPS_PORT=7443

Then apply the changes:

docker-compose down
docker-compose up -d

Make sure your reverse proxy in CloudPanel points to the new ports (7080/7443).

That should solve the issue — no more conflict with CloudPanel’s Nginx.