Having trouble playing games with people on the same network

I am a network admin and have made sure that the computers are communicating with each other.

We are trying to play Rise of Nations together but he gets a message that indicates he does not have permission.

I have scoured through all the game settings and his account settings for anything related to Multiplayer and have found nothing.

I have bought the game for myself as well as his computer separately.

Have trouble playing against my son as well on my home network. Look forward to any advice on this.

We have an open nat and receive no errors when doing the network test

We can join parties fine. We just usually can't play games together like apex, siege, or black ops4. Apex usually says something to one us about losing connection to the server while we're still connected while the other joins the game and black ops
says cant join lobby. I forwarded ports months ago hoping it would fix

I forgot to mention that he is 13 years old and the game is rated as teen.