Make sure that the following are enabled;
-WiFi
-Bluetooth
-GPS
-All IIDControl app permissions
Also, never try to pair the unit, the App takes care of the connection. Unpair or disconnect from any other Bluetooth devices from the phone when using the IIDTool.
*Some mobile device have an all in one GPS, Bluetooth and WiFi chip. All must be enabled even if the IIDTool does not use the GPS.