Diagnosis
The machine is going through the cycle, but the ice isn't being harvested. The most likely culprit is the ejector blades aren't turning, often because the ice froze into a solid sheet in the mold.
How to Fix It
Unplug the unit and open the lid. Look at the metal evaporator plate. If you see a solid sheet of ice or cloudy white ice stuck to it, that's your problem. Let the machine sit unplugged with the lid open for 20-30 minutes to let that ice melt slightly. Then, use a plastic tool to gently pry the ice sheet off. Once it's clear, plug it back in. The next cycle should produce individual cubes that drop.
If That Didn't Work
The temperature in the room might be too warm. These portable units struggle in hot rooms. Make sure it's in a spot under 90°F and has at least 5 inches of space on all sides for air circulation. Poor ventilation makes the freezing process inefficient.
Heads Up
Don't try to chip the ice off with force. You can permanently dent the evaporator plate, which will ruin its ability to make ice. Patience and melting is the safe method.