ur account is stuck, you may check this thread and post ur issue it may help staffs look into this kinda problem but as said in below GM cannot manually disconnect ur character presently so u have to wait until a server check (which will disconnect all characters from server)most likely https://royals.ms/forum/threads/getting-the-already-logged-in-message-click-here.124442/
there is no future server check announcement currently and just been one early today, so u probably have to wait few more days before u can play this character