Unable to join network 'ChimePro...'

Trying to set up a ChimePro. Just installed a Ring Doorbell, and it seems to work OK. but when setting up the Chime Pro, I keep getting "Unable to join network ChimePro-8108D8" on my iPhone after plugging the ChimePro into a wall power socket. The "Ring" logo on the Chime is supposed to be "slowly" fashing. It's flashing, but not a slowley as depicted in the video. My iPhone is about 3 feet away from the ChimePro. The wall socket is about 25 ft from my internet router. Any ideas?