Inspect the door gasket for any visible signs of damage. A torn or damaged gasket may prevent the door from closing properly. The door gasket should be firm and resilient, without cracks or bulges. If the door gasket shows signs of wear, a replacement seal kit is available for purchase online or from your local Bosch appliance dealer.
Examine the door latch. If the door latch is bent or out of alignment, the washing machine door will not close correctly. Determine if the door has been bent or if it swings freely. The problem could also be caused by a faulty door interlock. To access the interlock, you will need to remove the door seal. Be sure the washing machine is unplugged before attempting any "do-it-yourself" repairs since electric power is supplied to the interlock. Some Bosch washing machine door interlocks have a rubber or plastic tube connected to a plastic pressure chamber attached to the tub. Using air pressure, the sensor detects if the water has completely emptied before allowing the door to open. The sensor may be damaged and will need to be replaced.
Inspect the hinge. The hinge is one of the easiest damaged parts of the washing machine. If the hinge is twisted or the door is out of alignment, the door will not engage properly. See if lint or other debris may be keeping the hinge from working correctly.
Do not overload your Bosch washing machine. Avoid forcing the door closed. If the door is slammed shut, the latch can be damaged.