Diagnosis
The three-beep error means the safety lid switch isn't engaged. The unit thinks the lid is open or not locked.
How to Fix It
Check the lid is fully closed. Listen for a distinct click. Look at the lid latch on the front. Make sure it's fully snapped down into the base's catch. Open and close it firmly a couple times. Wipe any crumbs from the latch area.
If That Didn't Work
The micro switch inside the base, behind the latch catch, might be faulty. Unplug the unit. Inspect the plastic latch mechanism for cracks. If it's broken, you need a new lid assembly. If the mechanism looks fine, the internal switch likely failed.
Heads Up
Never try to bypass the lid switch. It's a critical safety feature to prevent the heating element from operating with the basket out.