My Team Fortress 2 team offers something called a reserved or reserve slot whereby one can purchase guaranteed access to a server like knowing you can always get a seat at your favorite restaurant.  A fellow purchased one and then shot me a message that it wasn’t work. I checked his credentials, verified his identity, and asked him to check again. No luck. I removed his slot and re-added it. No luck. I asked him what server he was trying to join. He proved an IP address… for another team’s server.