The Connect app works on one smart device but not on another

Your non-functioning smart device may not be compatible.  You can only use the Connect app on a compatible smart device.  Check your smart device compatibility here.

If you have used (paired) the Connect controller with another smart device and then you return to the original smart device, you must first unpair the Connect controller from the second smart device before pairing with the original smart device again.  See links below on how to unpair and pair: -

How to Unpair my Connect controller

How to Pair my Connect controller