When you open the vehicle with your badge, the terminal in the glove box asks you for a 4-digit PIN code according to the DD/YY fomat(example: if you were born on 24/06/1995, your PIN code will be 2495).
When you created your account, make sure that you have entered your date of birth correctly.
If your PIN does not work, the terminal will tell you that your reservation was ended automatically and that the doors will lock in 5 minutes. Exit the vehicle, lock the doors with your badge, then call our customer service to re-activate your booking (+49 30 30 80 80 65).