:O oh no!! So far I had one other report of 2 person trying to play both on phones that didnt work D:
Is there an error message that shows up in the top of the screen?
Also, can you go on this https://tomchen.github.io/symmetric-nat-test/ and tell me if it says you are in a Symmetric NAT (according to the docs, this is the main issue that could prevent people from playing)