BOSCH dishwasher not starting?

My BOSCH Maxx freedom performance dishwasher turns on, starts to fill up but wont actually start washing?? The only thing I think this could be is that the latch on the door is locked even with the door open. It has worked in the past and even recently worked with the latch being in the closed position, however nothing is now happening. I have tried to flick the latch back open but wont move from the locked position. Is it electrically timed or connected with start and finish of the cycle? Can you help? thanks.