This usually happens following an untimely disconnection or a connection issue while zoning in-game with a specific character.
If possible, we would first advise you to log on to the game from an alternative location e.g. Different PC or console.

NOTE: If you log in from someone else’s PC or console, do not log in as a Member but rather as a Guest. This avoids the saving of any log on information to that terminal.

Also, although this issue often only affects a specific character, we would advise you to refer to this article. This will help you to check and reset your connection.