Nostalrius Begins - Quality wow vanilla realm (1.12)

when i am trying to log in my account, it quickly disappears that you are disconnected. And on the website, it says login failed, bad credentials.
I am sure I did not do any thing against the rules.
No gold trafflicking.
Did not trade with anyone recently, only purchased some potions in AH.
My char name is Xiaoruan on PVP realm
I appreciate your help