IP phone Caller ID - problem

When making an outside call, my DAHDi extensions all ID themselves with the correct number, but my single IP phone refuses to do so. It comes up as “Anonymous” <0000000000>.

There is one bizarre exception to this: when I call my voip provider’s 911 test number it IDs correctly. Every other cellphone and land-line it calls winds up showing anonymous or private.

Can anyone suggest what might be wrong?

-FreePBX 2.9.0rc1.3
-Grandstream GXP2120

Grandstream just updated their firmware for the GXP2120. The new version of firmware seems to have solved the problem. I am not sure why the problem happened in the first place and I don’t know how the firmware fixed it, but at least it is now working.