On occasion there will be situations when a locker door does not open when it should. The first troubleshooting step is to authenticate at the kiosk with mobile or card, and determine if the locker's lock 'clicks' or not. The 'click' noise represents that the lock has received the signal and is attempting to open.
If the lock 'clicks'
This usually means there is pressure on the locker door from the indies holding it against the latch, preventing the release mechanism from opening. Try gently pressing on the locker door to close it slightly as the user authenticates at the kiosk.
If this works, test the locker again, it might have been a once-off problem. If the issue happens again the lock needs to be adjusted the moved forward slightly.
If the lock doesn't 'click'
In this case either the lock or wiring is faulty and the locker needs to be forced open. This procedure should be completed by someone strong, if you are not comfortable to do this please raise a support ticket.
To force a locker open, manually open the lockers above and below the faulty locker.
Firmly hold the locker door from the top and bottom edge on the lock side rather than the hinge side, with your fingers wrapped around to the back of the door. Give a short, sharp pulling action to 'rip' the door open.
This procedure will damage the latch, which will need to be replaced - please raise a support ticket for this. Take the locker out of circulation until a new latch can be fitted.