DIAGNOSIS The dishwasher is in a lockout state, most likely because the door isn't fully latched. The control panel won't respond and just beeps if it doesn't sense the door is securely closed.
FIX First, check the door latch itself. Open and close the door firmly—you should hear a distinct, solid click. If it still beeps, open the door and look at the U-shaped latch hook on the door itself. Make sure it's not obstructed by a utensil or a piece of trim from the tub. Next, check the strike plate on the tub frame where the latch hooks into. Give it a gentle wiggle with your fingers; on some units, it can get slightly misaligned during shipping or installation. If it's loose, you can usually recenter it and tighten the two small screws that hold it.
IF THAT DIDN'T WORK There's a small chance the control board has entered an error state from a previous power surge. Try a hard reset. Turn off the circuit breaker that powers the dishwasher for a full 60 seconds, then turn it back on. This clears the control board's memory and often resolves a glitchy lockout.
HEADS UP Don't keep slamming the door trying to get it to latch. If the strike plate is truly out of alignment, forcing it can damage the plastic latch mechanism on the door, which is a more expensive fix.