Having connection issues with just one player

My brother and I both host our own games and have the Ultimate license. Last week I tried to join HIS game and couldn't join despite the fact everyone else in the party could. Now this week he's trying to join MY game and cannot despite the fact that everyone else in the part could. We tried clearing the player data cache, ensure ports were forwarded...all the normal stuff with no luck.

Seems odd it seems to be just the two of us having issues with each others games. Any ideas?

Use local/lan ip address and not wan address or alias.

@mysterowl - damned's recommendation assumes you're on the same network. If using the local/LAN IP address doesn't work (if you're on the same network), please provide more info about you and your brother's network setup.