New Chime Pro (2nd Gen) Won't Connect To Network

I just purchased a Ring Video Doorbell 3 and a Chime Pro (2nd Gen). The Ring Doorbell is set up and operates fine. I am having a problem setting up the Chime Pro. The Chime setup seems to go smoothly until it gets to the part where it connects to the Wi-Fi network. After about a minute, the setup fails and the ring light on the Chime turns red. And, I get an audible message that says "Connection failed due to a poor signal - locate closer to router and try again". The Chime was plugged into an outlet that was 15 feet from the router and had a direct line of sight with no obstructions. My phone (Android, Pixel 3 XL) says that I have an "Excellent" signal. The router is an ATT U-verse 5268AC. It's a dual-band router and both 2.4Ghz & 5Ghz are turned on in the router. My phone connects @ 5Ghz. I called Ring support and they were not any help at all. They just had me do what I'd already done 3 or 4 times before I called them. They also told me that my Chime could only connect @ 2.4Ghz and suggested that I Contact Amazon and request a replacement - which I have done. I noticed one odd thing during the setup for the Chime. When it was attempting to connect to the Wi-Fi network, it did NOT prompt for a password. The doorbell setup DID ask for a password. Is this normal? Are there any suggestions to make the Chime Pro (2nd Gen) connect to my network?