If you have modified your server according to the current solution that we find on the internet, please rollback these changes first, including:

If you set up a basic UFW firewall to deny by default and allow HTTP and SSH, this will appear secure—but it will not block Docker from starting containers bound to other ports. This issue can be hard to catch, as UFW and Docker are separate systems. UFW is unknowingly lying to you and will not show open ports from Docker containers.