Video Doorbell Help

We didn't have a physical doorbell in our home.  Also important to note, we do NOT have a chime box.

We ran a new wire to the front of the house to install the Xfinity doorbell.

It has the proper voltage, 18.8 volts at the wires.  The transformer is the recommended voltage as well.

We get the doorbell hooked up, paired and on line just fine. 

We ring the doorbell once and after that it goes black, the doorbell is dead and we can't bring it back on line. 

We are on doorbell #2 with no idea on what the issue is. 

Please someone help!