Sometimes if drain is clogged or water leaks in the base of appliance the dishwasher control believes previous cycle is still not complete hence, it won't start.
Please try this:
You may unplug it and remove the plinth (base panel below the door) of the appliance.
You will see a metal cover, remove this and then you can try and soak the water up from the base there.
After this is done, check the drain hose where it connects to house drain and make sure it is not clogged.
Then clean the mesh filter from inside and make sure it is not blocked.
Reconnect everything and plug it back, please let me know how it goes.
It should work however, if the issue is still there then I am afraid the power board is faulty and will need replacement.
Please do not hesitate to ask any follow up questions.
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