The blue glowing LED indicates that the motion sensor is deactivated.
If you want to reactivate the motion sensor, you can easily do so using the light's button:
Variant with fixed light color 3500K: 4× short press: the status LED goes out, the motion sensor is active again.
Variant with Color Tune 2700K-4000K: 4× short press of the upper button surface of the Smart Switch: the status LED goes out, the motion sensor is active again.
If you want to reactivate the motion sensor with the GRAU app, proceed as follows: