I did that to myself yesterday. Make sure you have the "Chihiros Solenoid Controller for CO2 Regulator" and that you have connected it between the power supply and Regulator Pro. Then check whether your phone has Bluetooth activated in the settings.
In the app it is shown as Regulator PRO, not limited
Otherwise, unplug the regulator from the power and plug it back in. And restart the phone. And wait a bit