DIAGNOSIS This is almost always a water temperature issue. The water in the reservoir is too warm when the freezing cycle starts, so it doesn't freeze solidly in the allotted time.
FIX You need to start with colder water. Don't refill the reservoir with room-temp tap water. Instead, use chilled or refrigerated water. 1) Fill a pitcher and put it in your fridge for a couple hours. 2) Pour that cold water into the ice maker's reservoir. 3) Run a cycle. The cubes should come out noticeably thicker and more solid. Keep using pre-chilled water for the first few batches if your kitchen is particularly warm.
IF THAT DIDN'T WORK The other possibility is the unit's ambient temperature is too high. Make sure it's not right next to your oven, in direct sunlight, or in a cabinet without ventilation. It needs space for the compressor to breathe and shed heat.
HEADS UP The first batch after a fresh water fill will always be a bit slower and the ice might be weaker. The system works best when it's in a consistent, cool environment and you're maintaining the water level with cool water.