Desperate - Help with failed login using a Spectralink phone

I have a client that ordered a Spectralink 8440 phone.  The phone will not login to Lync.  I get an error "Microsoft Lync Sign In has failed"  No matter what I try I cannot get the phone to log into Lync.

Now to make it more confusing.  If I use the same phone and only change the Lync login information to my account it wil login to my Lync servers and it works if I am on my wireless or at the client on his wireless.  If I try to login as the client from my location or his it will not work.  But I can use that same account and login to the Lync desktop client from his site or mine.  The only thing that doesn't work is this phone going to the clients Lync server.

Thanks in Advance.

Todd