Character name problem

Hello there.
I have recently joined Warmane by invitation of my friend and when came i created random character so i can preserve nickname for my real character when get back from a trip.I have returned and deleted a character and created main but whenever i try to put nick it says it's unavailable.I attempted to resolve this by many way which included cache delete,WoW reset,realm change etc. and none worked.However i noticed there is a (1) below the number of characters even if there is none.
Any help to resolve this problem would be very helpfull.
Thank you in advance.

you just need to wait a server crash / restart ( which already happened on Wotlk realms)

Thank you a lot <3