DIAGNOSIS The unit is going into a safety shut-off. This is often because the humidity sensor thinks the room is already at your set target, or there's an issue with the internal condensate overflow safety.
FIX First, let's rule out the easy stuff. 1) Check that the bucket is seated perfectly and the float isn't stuck. 2) Set the humidity control to 'Continuous' mode (the icon with the raindrop, not the % symbol). This bypasses the humidity sensor and tells it to run non-stop. 3) Let it run. If it now runs normally and collects water, the issue is with the room humidity sensor or your target setting was too high. 4) If it works in Continuous, switch back to a low humidity target (like 45%) and see if it behaves.
IF THAT DIDN'T WORK If it still cycles off quickly even in Continuous mode, there's likely a problem with the electronic control board or a thermal overload switch tripping. Listen closely right after start-up: you should hear a relay click about 3 minutes after the fan starts, which is the compressor engaging. If that click never happens and it shuts off, the control board might be faulty.
HEADS UP These units have a 3-5 minute compressor delay timer on start-up to protect the system. So don't panic if it's just the fan running for a few minutes before you feel the air get warm—that's normal.