Problem with Old Nutone and Ring Doorbell

Have a Ring Video Doorbell connected to a very old (30+ years old) Nutone Concerto Doorbell. Worked perfectly for 6 months then suddenly it decided to ring randomly about 3-4 time an hour. I called support and they said it was not compatible with the RIng Doorbell. I unhooked it and put the old 2 wire doorbell back on and works perfect. I don't buy that it is not compatible when it worked fine for 6 months. Any thoughts?