Why am I unable to enter an instance?

Please be aware that if a player had their dungeon difficulty set to Heroic Mode before 2.0.3 they may be unable to enter any instances.

This is currently being investigated and we hope to have it resolved as quickly as possible. For now, a work around has been found that will reset your difficulty.

Please type the following command to set your difficulty to Normal Mode: /script SetDungeonDifficulty(1)

Please note that you will need to type out the command as presented.