Did the Tech install the Hopper, or was it a self install?
If it was a self install, you can't connect the Hopper to the Node if the Joey is connected to the Node via coax, and the Joey also needs to be unplugged also.
Try unplugging your entire system, Remove the coax from the back of the Joey.
Then Power up only the Hopper.
Once the Hopper is fully powered up, also make sure moca bridging is Enabled.
Then go to the Joey, install the coax and power it back up.
If that doesn't work you either have a bad node, or Bad TAP if you have one, or possibly a bad wire.
I'm assuming you have a Solo node?
If you had a Duo Node, you could try the other HOST port.