Nostalrius Begins - Quality wow vanilla realm (1.12)

Hello everybody.
I've played on this server since it opened. I had account named KVAZZMUSIC, and everything was great. But yesterday my friend decided to join me and I created the second account, KVAZZMUSIC1, but used the same email. And now i cant use my first account, because UNABLE TO CONNECT. Connection with second account is normal.
What can I do? How can i change email of my first account?

you are allowed to make multiple accounts on one email address.
so changing the email address has no influence.

a lot of users have second accounts with same email and no problems. so it is definitely no issue regarding this.

It's weird. Because problems with first account started right after creating a new one.
So, what's the reason? I use one computer, one IP, one Wanilla client, i really dont think that there are issues from my side.

P. S.: I deleted everything I could delete, I was changing realmlists hundred times in a row, nothing helped. I repeat - new account is working great right now.

Problem is solved.