When trying to pair with the Doppler, make sure you're entering a 6 digit code rather than 4. The last two digits are on the bottom right. If the 6 digit code does not work, unplug the power from the Doppler, remove/forget the Doppler from the Bluetooth system menu if it's there, plug the power to the Doppler back in and try again. If the pairing still does not work, please try a different phone or tablet with iOS or Android. If this still doesn't work please reach out to support.