Diagnosis
E1 is a temperature sensor error. The sensor on the evaporator thinks the unit is overheating or not cooling at all.
How to Fix It
Ensure the unit has at least 4 inches of clearance on all sides, especially the back. Overheating from poor ventilation is the most common trigger for E1.
If That Didn't Work
The sensor itself might be faulty or its connection loose. This requires opening the rear panel to check—if you're not comfortable, this is a service call.
Heads Up
Running it in a hot garage or next to a dishwasher will consistently cause E1 errors. Ambient temperature is critical for these compact units.