2 PS4s connected to same network can't play together

I have 2 Playstation 4s connected to the same network. We cannot get them to join the same game at the same time. My brother and I used to do it all the time but one day it just stopped working. We can only play one at a time. If I join my brother's game he gets kicked out and the same happens to me when he joins my game. We've spent all our money on setting up 2 playstation 4s and 2 TVs in the same room just so we can play battlefield together. Its the only game we play. If anyone knows how to fix the problem I'll love you forever.

I hope we don't face the same problem on Battlefield 1!