I punched in some settings and copied others using copy and paste - big mistake!
With my copy and paste I had an extra character which was a space.
It looks like Aastra phones don't like the extra space in a field where they expect an ip address.
It took me about 30 minutes but I eventually found the extra space - removed and everything registered nicely. What bothers me is that this is the second time I've managed to make the same mistake. I am betting others are going through this exact same thing - hope it helps someone.