Diagnosis
Water pooling under the unit indicates a blockage in the internal condensate drainage path or the unit is not level.
How to Fix It
First, ensure the unit is perfectly level front-to-back and side-to-side. Use a bubble level. Tilt can cause water to spill from the evaporator coil pan. Second, check and clean the internal drain hole and channel. This requires removing the bottom service panel and carefully clearing any debris.
If That Didn't Work
The leak may be from a disconnected or cracked internal drain hose. This is a disassembly repair. Alternatively, in very high humidity, the auto-evaporation system can be overwhelmed, causing overflow. Manually drain via the drain plug more frequently.
Heads Up
If the leaking water is greasy or has a chemical smell, it could be refrigerant oil from a serious leak. Stop using the unit immediately and contact service.