Be sure the use https. http sometimes doesn’t automatically forward for me.
You can connect via an ssh tunnel. Might be easier to find the issue with the GUI.
ssh in with ssh -D:2000 urname@ipaddress. Then set your local browser to use socks5 proxy with 127.0.0.1 as address and 2000 as port. Then browse to the https://ip:10000 as all traffic will go to the server first, then look for the ip. Which will connect since you’re on the same “lan” via the ssh tunnel.
Not sure about CentOS but on debian iptables is not the default firewall for virtulamin. Its firewalld.