This tutorial shows what to do if the phone is not connecting to the MicroCell.
INSTRUCTIONS & INFO
Verify the AT&T 3G, 4G, or 4G LTE wireless cell phone number has been added to the approved user list. Note
If your cell phone does not display 'AT&T MicroCell' or 'AT&T M-Cell':
Restart your 3G, 4G or 4G LTE cell phone. Turn your cell phone off and then turn it back on.
If restarting your 3G, 4G or 4G LTE cell phone does not resolve the issue, then restart your MicroCell. Unplug the power adapter from the wall outlet, wait 10 seconds, then plug it back in. It may take an additional 30 minutes for the Network light to turn solid green.
If your issue cannot be resolved via the troubleshooting steps provided, please visit AT&T MicroCell Help or call AT&T Support at 1-800-331-0500.