Linux IPTables Firewall. Apply Configuration Error

Linux
CentOS Linux release 7.9.2009

Hi, I have a problem with synchronization iptables rules in Cluster Firewall Servers. When a push the button “Apply configuration” I get this message:

Failed to apply configuration : Error reading response length from fastrpc.cgi :

Thank You.

That maybe means TLS is failing, i.e. a bogus or expired certificate on the other server.

Could also be a firewall. You need ports 10000-10100 open on every Webmin server that is using fastrpc.

Thank you for answering me. Could I ask you, where Is TLS settings?

Currently firewall provide connection in all ports.