WotLK What is this window that keeps poping up?

[Redgar]

When randomly playing there will be a message pop up saying enter the password to: cz239124 or something, do i need to enter a code of some sort?
also how do i find a guild?

[skullatbash]

can you post a screenshot of thai pop up?

[NightBoss99]

This happens quite often to me too, and I think the problem has to do with the Carbonite addon. I am not sure how to fix it, it sometimes just disappears for a while , then comes back. Noticed it happens when I fly or use hearthstone, aka when moving into different areas?