Hi Pete.

Could you please confirm which mobile device you are using, also please try the below

1. Check if Bluetooth is enabled.
2. Check if phone is paired and connected to CODE.
1. In order for Gateway to connect to CODE, phone must be first paired and connected to CODE.

If Gateway still can't connect to CODE, please try the following:

1. Restart CODE.
1. If that doesn't fix the problem Go To Next Step.
2. Restart Bluetooth on phone.
1. Turn Bluetooth off -> wait few seconds -> turn Bluetooth on.
2. If that doesn't fix the problem Go To Next Step.
3. Restart phone.
1. If that doesn't fix the problem Go To Next Step.
4. Go to Settings -> Apps -> See All apps -> Menu (3 dots at the right top corner) -> Show System -> Look for Bluetooth -> Storage -> Clear Cache
1. This step is only for Android device
2. If that doesn't fix the problem Go To Next Step.
5. Restart Bluetooth on CODE.
1. Hold buttons REV + POWER, while turning on the amp. 
2. Then Hold STORE button to confirm Clearing Bluetooth.

Regards

Marshall Support