Printer is not in Wi-Fi setup mode. The light must blink.
Restart setup mode. Swipe down on the display to open the Dashboard. Touch the arrow, then Network Setup. Select Restore Network Settings. Confirm Yes. Wait 60 seconds. Close and reopen HP Smart. Try connecting again.
If that didn't work: Device is out of range. Move your computer or phone closer to the printer. Check for VPN connection on your computer. Disconnect from any VPN before installing HP Smart.
Heads up: On a mobile device, enable Bluetooth and location services. The app needs them to find the printer.