Just enable Bluetooth settings on your iOS device. DO NOT Need to connect Bluetooth Name on iOS device. Then connect the Bluetooth device name in the OBD app setting.
Step1: Open the app and click on:"SETTINGS".
Step2: Click on:"OBD-II interface type".
Step3: Select connection method: "ELM".
Step4: Click on:"OBD-II data port".
Step5: Click on:"AUTO".
Step6: Return to the home page after setting the correct connection method.