New Gateway will not activate

I received a new Xfinity gateway (X8?) and attempted to set it up using the app. Once connected to coax cable and power, the light initially turns yellow and then blinks green. I tried both with the new coax cable packaged with the gateway, as well as with the old cable from the old gateway. Both work with the old gateway; neither works with the new gateway. I also tried power cycling the new gateway, disconnecting and reconnecting cables, ensuring everything is connected correctly, etc.

Is there a way to connect with support and speak with a technician? The app only offers to book an appointment to have a tech come to the house, saying that the cable connection does not work. However, the connection is fine - I get service to the old gateway.

Likewise, the automated chat app useless in this case and simply circles back to having me attempt to set up via the app, which I have tried several times, always with the same results.

Again, does Xfinity actually offer live support in any form?