Beeping Noise

The microwave suddenly started making random beeping noises. 1 beep, two or three minutes later, a series of beeps. Nothing for 5 or 10 minutes, then 3 or 4 beeps. I followed the trouble shooting tips in the owners manual as far as reminders and changing power level. Didn’t help. Unplugged it overnight. Plugged it back in today and it was fine for a few hours, then started making the beeping noises again. Any ideas, suggestions??? Thanks!!!