Ring Won't Connect After All Trouble Shooting

I'm hoping someone can help. I received a Ring Video Doorbell 2 for Christmas. I can always get it to connect first to the RING network, but that's it. After hours of repeated "there's seems to be something wrong with your internet connection" RING app error messages, hours of unplugging modem, unplugging router, resetting router, checking passwords, ensuring that I only attempt connection to 2.4ghz network, standing 8 feet away from router, standing 6 inches away from router, turning off cellular (apparently some known issues with iPhone sometimes) I called customer support RING said unit likely defective and they sent me another. New RING, same issues. Round 2 -- same error message, no matter what I try. All my devices are successfully connected to my router, including 3 Alexas. Some blog suggested that RING won't connect to wifi that's on channels 12 or 13. I went into my router admin and saw that it was on channel 5, but changed it to another just in case. No help. The same "there seems to be a problem with you internet connection." Using iPhone and ASUS router. I've never had this much trouble connecting to a device before. If anyone can help....I haven't opened my front door in 2 months of this. (Just kidding about that, but still could use some help).