Power problem when using mechanical bell function.

2 year old Ring Pro works fine.Today I turned on the "Ring my in-home doorbell" (RMIhD) feature.It worked once, but then we found that the Ring Doorbell & the transformer lost power.We flip the circuit breaker and everything works again.... once... once again.Since the RMIhD setting change was the only difference between today and the previous 2 years of a perfectly functioning system, we switched it off. Ring Doorbell works fine with multiple tests. Also, the Device Health shows "Very Good" at 4066 mV. What are some troubleshooting steps that I can take towards using the RMIhD feature?