friend cant join my non-dedicated server

So my friend and I play ark through my non-dedicated sever, we've been playing for a long time on different maps everything was working fine. A few days ago we tried to play and when I sent him an invite, he tried to join but it said “you do not own this DLC” we kept trying a few more times but nothing. We also tried doing other DLC it still didn’t work. It’s weird because he can play the DLC on single player, but he can’t join my non dedicated server. It anyone expensing this as well or even better have a fix for it.