[Question] Players can't find Server on Browser?

[Aggamemnon]

My son just verified his files this morning as was suggested and performed his first time setup. He went into the Server Browser to find my Server and could not see it. It is there for myself and most of my friends, yet I have also heard from others that they cannot see it either?

I checked all his settings and they look fine, the same with his Browser settings. Yet when I checked on his system I could only see 41 servers?
I got him to connect via the Steam Favourites and he could do so, but the odd thing was that when he joined it said my server was running 'Realism' when I have got it set on 'Action'?

I am just about ready to delete his 'Local Content' and re-install the game entirely, but thought that I may find a solution here. Does anyone know what may be causing this? I have heard from some of my friends that this is occuring to them as well.

With mine and many others it is showing fine on the server browser and with us we get around 200 servers (Ranked) showing.

Another thing: Even when he adds the Server to Favourites in the Game Browser and restarts the game it does not show up.