Problem hosting a server

Hello people,i've been trying to host a BTE server for over 2 days,i have only managed to open the port 14242 with TCP,It made people be able to join but when they started playing the game they 'crashed' And about the UDP,it only worked when i had put a different port,But i don't know how to make them join this different port i have chosen,i have already tryed to delete all other default ports except the HTTPS,HTTP and FTP and it still didn't work,Me and my friends are desperately wanting to play the game together but we're stuck on this problem,all of us.

Please help.