Before securing your sensor around your torso, make sure the skin under the electrodes is clean.
Humidify the electrodes to improve the signal quality.
Synthetic clothing that comes in contact with the sensor can cause some interference during the measure
Check that the electrodes are not obstructed by small skin residues. Use a cleansing gel if necessary.
Delete and reinstall the application.
For Android phones, clear the cache or delete the application data in the phone settings. You'll find instructions here.
Have a look at our blog article which explains how to get a clean RR recording.