Seeing as how you're posting here about it, you're probably connected to the internet; check. You may have a routing problem between you and the gw server closest to you; this you can not fix. Check your ports and make sure your firewall isn't blocking anything, otherwise you're SOL.
That usually happens after an update. The time it takes for the server to reload the alterations that have been made can be compounded by the amount of pings the server is getting from all of us no-life basement-dwellers.
I am logged in but I can't go to certain guild halls in my alliance and when I am trying to warp it gives me a message that your party is waiting to enter a mission would you like to leave.... but... I am the only person in my team lol.