DIAGNOSIS This is a classic setup handshake failure. The opener's MyQ system is trying to connect to your network but can't complete the final step, usually because of a router setting or a weak signal.
FIX First, power cycle the whole system. 1) Unplug the opener from its ceiling outlet. 2) Turn off your router/modem for 30 seconds and turn it back on. 3) Once your internet is fully back, plug the opener in again. Wait for the light to go solid green. 4) Now try the setup in the MyQ app again, making absolutely sure you're selecting your 2.4 GHz Wi-Fi network (it won't work on 5 GHz).
IF THAT DIDN'T WORK Your router might be using a security type the opener doesn't like. Log into your router's admin page and temporarily switch your 2.4 GHz band's security from WPA3 to WPA2-PSK (AES), or just WPA2. Try the setup again. Switch it back after you're connected.
HEADS UP During setup, keep your phone within 10 feet of the opener's motor unit. The app communicates directly with it via Bluetooth first, and a weak phone signal can botch the whole process.