Is this a new conection (eg VOIP on FTTP)?
Is it when you call out or what users get when they call in?
Occsionally it means just what it says,. But if you get it all the time or it is mixed with 'number not available' and other messages it means your connection isn't finished yet.
It may come right after about a day or you may need to private message a mod with your details.
