Diagnosis
This is typically a defrost cycle or an over-temperature condition triggering the auto-shutoff.
How to Fix It
Verify the room temperature. If the room is below 65°F (18°C), the evaporator coil will frost over. The unit will cycle off to defrost. This is normal. Move the unit to a warmer space or raise the room temperature.
If That Didn't Work
If the room is warm, check for restricted airflow. A dirty air filter or blocked intake/exhaust will cause the compressor to overheat and trip the thermal protector. Clean the filter and ensure 12 inches of clearance on all sides.
Heads Up
Short cycling (on for 5 min, off for 5 min) in cool conditions is expected. For continuous operation, use the "Continuous" mode, not the "Target RH" mode, which cycles based on humidity.