I unplugged the AT&T Micro Cell to eliminate it form the equation and then reran the Radio test. Unfortunately, I received the same results.
To be thorough, if you unplug the microcell, I would recommend rebooting the GC3 while the microcell is powered down, or waiting a few minutes, prior to attempting a cell test.
It would be better to add your GC3 number to the whitelist as a test. If it can indeed communicate it might improve signal. Note that the number you’ll need to add is not found on the module or listed in panel settings. You would want to email customerservice@suretyDIY.com and request the number associated with your module