Doorbell power issue

Ok. Had doorbell installed. Was working perfectly. Even picked up my girlfriend coming into the house. About 2 hours later it wasnt funtioning at all. No power to it. Checked wiring and it was still connected properly. Maybe transformer failed? House is 32 years old.Any ideas would be appreciated.

check for tripped breaker. also, to verify the doorbell still functions, remove & power up via microsd (on the back under weather seal).

Thank you will try that.

Similar issue. Worked fine on first night. Then stopped. Replaced transformer and all is well now.