DIAGNOSIS Yeah, this one's common. The defrost drain hole inside the cabinet is probably clogged with dust or debris. When the unit goes through its auto-defrost cycle, the water has nowhere to go but pool up at the bottom.
FIX Unplug the unit. Remove all the cans and shelves. Look at the back interior wall, near the bottom. You'll see a small hole or channel. Use a pipe cleaner, a trimmed zip tie, or a blast of canned air to clear it out. Tilt the unit back slightly to help any standing water flow toward the hole. Wipe everything dry.
IF THAT DIDN'T WORK The ambient room humidity might just be too high for a thermoelectric cooler. These units struggle to dehumidify the air inside if the room itself is very damp (like a garage in summer). A standalone dehumidifier in the room is the only real fix.
HEADS UP Don't leave cardboard packaging or paper labels on cans stored inside long-term. They absorb moisture, fall apart, and can actually clog that drain hole.