Nostalrius Begins - Quality wow vanilla realm (1.12)

Hello, guys. I got my account closed, but I don't understand why. Character name - Sindella, mage 51. Never used cheats, bots, never traded account or something. Was playing wow 26-10-15, the game started to lag a lot. I logged out, turned off my computer and opened my girlfriend's computer using mobile internet to play without lag. And i couldn't do that beacause of errors (Unable to connect). Then I opened wow on my computer using home internet and got the message "this account is closed" or something.

Maybe it's anticheat error or something? I hope you can help me with this problem, beacause I really like to play this server and I have never used cheats or something like that. Waiting for your answer, thank you.

log into the website https://en.nostalrius.org/login
and check what ban reason is stated

if there is no ban reason / if you can't log in to the website you entered the password too many times and thereby locked yourself out of the account

in that case reset your password through the reset feature