I was talking with some of the Arma 3 community members and was asking if they had any luck getting registered for the Pro license - and many weren't.
So, for testing purposes I tried a different email account on my domain, and the same thing happened. I then tried a Google gmail and that worked.
This happened for both the license registration and the forum registration.
Are google email accounts the only way to register?
Best regards,
Zeak