Audio Video Problem with more than two participants

Hello to all members.
I installed Jitsi Meet in my network environment. Network environment is something like that:
Live IP is in firewall.
Local IP is in Jitsi Server with 172.X.X.X.
Another internal network scheme in locality is 192.X.X.X.
I have entered live IP and 172.X.X.X in sip-communicator.properties file in Jitsi Server.
Now it is sure that Jitsi is not required to be accessible from internet. It is just required in internal network.
It is working perfectly in 172 network.
DNS server resolves the domain for sending to 192 network.
Now when Jitsi is tried to be accessed in 192 network; it works fine with two participants however camera and mic stops working when another participant hops into conference. Is there any other configuration is required in Jitsi Server machine? Help is required in this regard. Thanks