As Scout is a security device itt requires a bonded / encrypted Bluetooth connection. In this case the connection is not correctly established. This can happen if the Bluetooth bond is forgotten / removed via you phones Bluetooth settings.
To fix this, remove the Scout from the Knog app, your phones bluetooth device list and the Find My app. Then perform a factory reset, add the Scout back to the Knog app and set the Scout up again.
You can find the factory reset instructions for Scout Bike here, and for Scout Travel here.
Do not attempt a factory reset if your Scout is armed or the alarm is sounding. In this instance, please reach out to our customer service team for assistance.