Closing as not a C2 bug, this is to do with WebRTC peer-to-peer connections and the network configuration. I have tested and successfully gotten the WebRTC example apps to work over 3/3.5G, but it depends on the network, and each carrier's network will be different. I really doubt they are blocking UDP entirely, since that is commonly used for better video and audio streaming performance. I'd guess however that if you try to host a game on cell data then it is blocked, because your carrier does not want (or explicitly forbids in their TOS) running servers over cell data, presumably to avoid over-burdening their network.