If by a return the lock fails to open the lock, we recommend you to check the following steps.
It is important to check the display in case of problems:
1. Is the display on? If it is off then restart it.
2. If something goes wrong with the lock, then reboot the display and try again.
On top of the display, you will find a black power button to start it up or reset it:
Sometimes it also fails because the location does not allow enough connection due to high buildings. Then try moving the Cargoroo cargo bike a bit to make a proper connection.