Need Appliance Repair Help? Ask a Technician for Answers ASAP
The door lock is bad or the main control board is. There is no way to know which as no test exists for this behavior. Buy the lock first and if that fails then replace the control board. Neither part is hard to replace. Any local appliance parts can look up anything you need by the model#.
Youtube has many videos on everything, so I would look there for one as this is not hard to do by anyone with basic skills using hand tools as I am well aware you are not a tech.