Video Doorbell Pro Dying

Tried resetting Doorbell Pro several times. Do not get any light, spinning or otherwise, white or blue. Power is good, internet is good, other devices work fine. No alerts, no video from doorbell. If I push the main button on the doorbell only the doorbell itself rings as does the mechanical doorbell. Two techs couldn't figure it out. One even sent me a new doorbell! Initial setup worked fine but two days later it died. Very frustrating!!