Ring Pro blowing transformer

Ring pro has blown out 3 different transformers. We installed the Ring and it worked for one ring then stopped. Was no longer getting power. Replaced the transformer and tried again but the same thing happened. Bought a third transformer and had an electrician install it, but the same thing happened again. The electrician said the transformer was blown from the Ring. There was an old doorbell hooked up , which was working fine, so it's not the wiring. What do I have to do to get this ring doorbell to work?