itunes Connect refuses AppleID

I can log into iTunes connect separately, but then this happens to me as well.

"I've been trying to publish a book I've created on iBooks Author to the iBooks Store but I'm having a bit of trouble with iTunes Connect.

I've set it up and signed the contracts and I can access the dashboard on a web browser with my Apple ID however, when I try to log into it from the Publish wizard on iBooks Author it keeps coming up with an alert message saying that "this Apple ID isn't associated with an iTunes Connect account", even though... well... it is.

I was wondering if it was a possibility I might have missed something along the way to connecting my Apple ID to the iTunes Connect? I don't know what to do."