Sometimes once the sensor has been initialized, it takes a while for the readings to settle into your average range. If you have just started a new sensor, it might sometimes take up to 24-48hrs to calibrate fully - usually waiting a few hours will do the trick. If after 2 days the readings are still going haywire, do get in touch with us. Remember to ensure you are tapping the right part of your phone on the sensor, or it will not read. Depending on your phone model, the NFC connection is on the top (iOS), or somewhere on the back of the phone (most Android models).
If your sensor is reading 0, please check that you have followed the in-app instructions for calibration fully. Sometimes it helps to try the setup again, and wait a while after. If the sensor reads 0 after a few hours of installation, do get in touch with us and send some screenshots so we can help as fast as possible! ✌️