wireless access point not working after gateway change

WAC104 not working (no wifi) after changing ATT fiber gateway.  The gateway wifi broadcaster is working, as well as other devices directly plugged into the new gateway.

The power, wireless and internet lights are on. Power cycling the unit, and turning the wifi on and off have no effect. Using the Netgear android app on my phone says the device is not there.

What do I need to check/change to get it working again?