I can't locate the error code. However, there are two bits of good news. First, the appliance has a 2 year warranty. Second, the following Neff webpage includes customer support contact information. They indicated being able to help you will the error code. https://www.neff-home.com/ie/
If your microwave oven doesn't appear to shut off when the door is open, you may have a problem with the door switch. The door switches, often referred to as interlock switches, provide power to the various components of the microwave. They are designed to interrupt the power when the door is open. https://www.fix.com/repair/appliance/microwave/doesnt-shut-off/
Inner layer of a microwave door is part of the metal cage that keeps the microwave energy inside and prevents potentially dangerous energy leaks.
To clean the inside of the glass the door will need to be dismantled - some doors dismantle easily and some don't and sometimes the door must be removed in order to dismantle...
Some doors remove easily and some don't...
It is very important the door is reassembled correctly and then tested for energy leakage.
If your microwave is making an unusual or loud humming noise, you may have a problem with the magnetron. This component is part of the high voltage circuit and provides the microwaves that generate the heat. If the magnetron is defective, it may cause a loud humming or buzzing noise.
It is not uncommon for some microwaves to quit prematurely.
What is generally more likely is the particular outlet it is on could also be faulty.
Check the outlet with another appliance, or contact Hamilton-Beach themselves to see if there is a known problem/remedy.
I would dispose and replace the whole. Sounds if the insulation has been compromised,making it dangerous and life threatening to use.They are now so affordable that repair is only justified on top end units.
If anything other than the light comes on when you open the door, unplug it immediately. Can you supply the model number and more detailed information about what's happening? For instance, you hear the transformer come on or the carousel starts turning.. Does the touch pad take input when you press buttons?
Note: if it's just the light coming on and making no sound, it could be possible it's in clock mode, waiting to have the time entered. If you press clock again, it would go to normal operating mode and work.
Please let us know.. Hope this helps.