Purple P3 ZVRS Z5 app

I'm having some issues with our firewall -- we installed Purple P3 and ZVRS Z5 app on Windows machine.  I've updated the firewall allowing certain outbound ports provided by the vendor. When a user made a call or receive a call, the other party can see the user, but this user cannot see the other party's video.  Any idea why?  I checked all settings. It seems to me that the outbound ports are working, and the traffic came back in but something is blocking them.