Since this morning, the community site of World of Warcraft has been flooded with comments from those player who failed to enter and go back to their ongoing games. Blizzard might be on their maintenance schedule and according to report, they officially announced it few days ago but until now, player are still experiencing the same and common problems with WoW. Try to check the Realm status for you to determine the current situation of your online servers.
Although we cannot completely confirmed this report, there are a lot of remedy you can get on the line. Just make a few rounds for it and a lot of players are just hanging there to catch what you're trying to get from them and ready to provide you the things you need for your problem. According to source, there are time that Blizzards servers are also unavailable due to some technical problem which could not be avoided because of its getting crowded environment.