Try the most common solutions first:
Turn the phone and Muscle Meter off and on
Turn your phone bluetooth on and off
Unpair your phone and Muscle Meter and repair
Ensure phone is within 5m of the device
Clear bluetooth cache and storage
Reset your phones bluetooth settings
Ensure your phone software is up to date
Still having issues? Check out the following links: Android or iOS
Please note due to the variance in Android devices some android devices may not work with the Muscle Meter. Android 12 or higher required.