The feedback isn't working.

If you aren't getting any feedback while singing your vocal part, make sure that you have hit the "record" button. If you only hit the "play" button, this will not record your performance and you will not get any real-time feedback. 

If you’re seeing your voice visualized on screen, but there is a delay between the audio and visual notes, you might need to recalibrate for your headphones and phone. To do so, go to the start screen, open the menu (top right), and tap “Calibrate Microphone.”

Using Bluetooth headphones? We do not support Bluetooth technology at this time for recording, due to some known and often documented issues this groundbreaking technology presents for music and recording.

You may also need to make sure that you are using wired headphones with a microphone so that the app is able to recognize your singing.