Protective cases and covers can sometimes interfere with the proximity sensor. If you have put a protective case or cover on your Nokia G60, try taking the phone out. If the proximity sensor is still not functioning as expected, you can test your proximity sensor using the diagnostic tools in the My Device app:
Open the My Device app Navigate to Device health Navigate to to device testing and press the button to get started Choose "Advanced diagnostics" Navigate to "Sensors" Choose "Proximity sensor" and test it as instructed
If the proximity sensor test fails, you may need to get your device repaired. You can check your repair options from the Support menu of the My Device app.