Mechanical chime does not chime

Ring doorbell pro has been installed by a electrician and cannot get it working correctly. Tried many things and double checked the product.-Voltage at 20v-wires all secure on the doorbell and mechanical chime-wifi is strong to the unit-no Alexa or google home taking notifications-doorbell shows proper video and motion notifications-when doorbell is pressed, it makes a chime from the unit itself from the outside but no chime from the mechanical chime in the home-Reset button has been held for 20 seconds and doorbell has been reset-Power has been shut down for 10mins and powered back up and reinstalled using the given install video-On the app, the mechanical chime has been selected and the in home doorbell is on.-have deleted the app and unit from my ring account and all reinstalled-reinstalled the old doorbell and works perfectly fine.Please help.