I'm trying to connect an M100 by VPN to my QDX6000 and it works. He (M100) can view and heard all from the QDX but the QDX
doesn't have image and sound from the M100.
Sounds like the VPN firewall is blocking video traffic one direction. Are you sure it is actually going through the VPN? Can you test by bring the laptop with the m100 to the site where the QDX is and place a call locally then work out from there?