Doorbell Elite not sounding mechanical chime

Ring doorbell Elite with Power over Ethernet has been working for over two years. Recently it stopped ringing the mechanical chime. When the black button is pressed the sound goes off at the doorbell and the blue light comes on but the mechanical doorbell does not sound off. I opened it to check all wiring is good, I shorted the two house door bell wires and the mechanical chime sounds off fine, just not when i press the doorbell black button. Any pointers appreciated.