Fault with onn om004?

I have a problem with the OM004 Microwave come grill as I tried to cook a jacket potato last night by the auto menu. only for the Microwave not to work & the readout to start counting down, & beep five times when the count downs completed. I found out that it sounds like the timer has been started but for the life of me I cannot cancel it & get the mircowave to start & cook I have now turned the unit off at the mains hoping it will re-set it's self, will this work??????