Videoconference on openfire

Hi all,
I’ve install an openfire server, with plugin: meetings, jingle nodes, Rdp and search. All work properly, so also videoconference on web, only video & audio conference call with Jitsi desktop fail when the partecipats are on different subnet. If all partecipants are on same subnet all work. RDP don’t work properly even.
Someone can help me
Thank you in advance.