Install new transformer for Doorbell Pro

Ring Doorbell Pro was working okay with a 16VAC 10VA transformer except Device Health regularly reported Power was Poor. It was installed with the Pro Power Kit in an existing mechanical chime.
So, decided to replace transformer with 16VAC 30VA. I install transformer, test with voltage meter, it works. As soon as I connect the doorbell wires to the transformer it dies and will not work. Why is the Ring Pro frying the new Hampton Bay transformer?