White Light Flashing After Reset...

We've just moved into a rental with a Ring Doorbell Pro. I held the button on the side down for 30 seconds to reset the device to add it to the app. It gives the "Welcome" message and the setup light spins for a couple seconds, then goes away. After a little bit, the white light starts to slowly flash. How do I get it to stay in setup mode? The owner says it has the power supply installed and the previous tenant had it linked to her account. When you press the button, the Ring chimes and the inside doorbell rings. Thanks, Don