Model Number:
Brand: Brand
Age: Less than 1 year

Model Number: WOC54EC0AS00
Brand: Other
Age: 6-10 years

Whirlpool wall mount Microwave/Oven combo has recently started giving this error message "Open and close door first" whenever we try to start the microwave. It only happens if the microwave has not been used for 5 or more minutes. According to Whirlpool product help website, this "occurs to avoid unintended starting of the microwave oven" which may be an over-the-top safety feature but it is an annoyance. It is possible that we may have changed some settings but we have tried powering it off at the circuit breaker to no avail.
How do I troubleshoot and fix it?