Alfa_Three

I was trying to play this game with my brother by using my phone as a mobile hotspot. I simply started as a host, it's done. My brother joining in, put the IP's adress which i found in my pc via command prompt (i'm not really sure if this is right step or not). But then he failed to connect as the error messages pop up says "Failed to connect to the server. This is often caused by UDP port 20595 not being forwarded on the host side, by a firewall, or anti-virus software." So, did i do something wrong in here ?