DIAGNOSIS The camera is likely on a 5 GHz network band or a band your phone isn't currently using for setup. The S340 requires initial setup on a 2.4 GHz band.
FIX Confirm your phone's Wi-Fi is connected to the 2.4 GHz network during setup. Many routers broadcast separate SSIDs for 2.4 GHz and 5 GHz. Connect your phone to the 2.4 GHz one. If your router uses a single name, temporarily disable the 5 GHz band in your router settings for the setup process. Re-run the in-app setup.
IF THAT DIDN'T WORK The camera may have entered a bad state. Hold the reset button on the camera for 10 seconds until you hear the power-down sound. Wait for it to fully restart, then attempt setup again from the beginning.
HEADS UP After successful setup, you can re-enable your 5 GHz band. The camera will stay on the 2.4 GHz network for operation.