Hi, FIrst, I see a ton of posts about this topic, and I have scrubbed through them to no avail. I have a new 3CX system setup and it is working great at our offices (which are also remote as we have 3CX installed in a data center). Problem is on Verizon FIOS networks, I am getting NO audio on any phone, device or other. It's the same on iPhone apps (bria), and now my Linksys SPA 942 (both when configured in the office work great). Server shows RTP packets received. I've setup rules on my router to ensure the RTP ports are open.....not sure what else to try. Anybody have any ideas ? Thanks !