Diagnosis
Yeah, this one's common. The dishwasher is hitting a snag and going into a diagnostic mode. The three-beep error on this model typically means it's having trouble filling with water, usually because the float switch is stuck or the water inlet valve is clogged or failing.
How to Fix It
First, power it off at the breaker for a minute. Open the door and check the bottom for any standing water. Look at the round, white plastic float assembly in the right-front corner of the tub floor. Manually lift it up and down a few times to make sure it moves freely and isn't jammed by a piece of debris. While you're there, clear any food bits from around the filter and drain area. Power back on and try a rinse cycle.
If That Didn't Work
If it still beeps, the issue is likely with the water inlet. You'll need to check the water supply valve under your sink to make sure it's fully on. If that's good, the inlet valve on the dishwasher itself might be clogged with sediment or have failed. That requires pulling the dishwasher out to access and test it.
Heads Up
Don't just ignore the beeps and restart it repeatedly. If the float is truly stuck in the 'full' position, you could end up with an overfill situation, though these models do have a secondary overflow protection.