Register Failed on T22P to MyPBX U100

[Firewall]

Problem has been resolved as per the following:

• On the phone config (under account /register), both "register name" and "user name", must be the extension number.
• In the PBX for the extension, register name must be the extension number as well.

I had everything named as the 'Reception' (as this phone was for Reception), but authentication won't work unless the above 2 conditions are met. This was not in the doco that I could find when I was setting up.