DIAGNOSIS It's short-cycling. The most likely culprit is a dirty or faulty humidity sensor, which is causing it to misread the room and toggle on/off.
FIX First, clean the sensor. Unplug the unit. The sensor is usually a small, plastic-covered component with tiny holes, located on the back near the top. Wipe it gently with a dry, soft cloth to remove any dust or film. Also, make sure nothing (like curtains or furniture) is right up against the back of the unit, as it needs to sample ambient air.
IF THAT DIDN'T WORK The other possibility is the 'Smart Dry' or 'Closet Dry' mode is activated. Check your control panel. If 'Closet Dry' (a little hanger icon) is lit, it's designed to cycle frequently to protect delicate items. Turn that mode off and set a specific target humidity (like 50%) instead.
HEADS UP If you have it in a very small, enclosed space (like a tiny bathroom), it can actually dry the air too fast, hit its target, shut off, humidity rises quickly from showers, and turn back on—creating a rapid cycle. In small rooms, a smaller unit might actually be more appropriate.