Ring Pro Doorbell/new transformer/no power

I installed a Ring Doorbell Pro and also installed a new 16 V - 30V max transformer. The doorbell worked perfectly until mail man rang doorbell, then lost all power out of the transformer to the doorbell. On the app, device health shows 0 Volts. I got a replacement transformer with the same voltage, and again it work for about 1 hour then again the ring has 0 V. I have the Pro Power kit wired in correctly as well. I have 120V coming in to transformer and 0 V coming out of transformer. Please help. Not sure why this keeps happening? It worked better with the old 30+ yr old underpowered transformer, but I threw it out already so now I have no doorbell :frowning: