DIAGNOSIS The unit is running in fan-only mode. The most common cause is the exhaust hose not being fully connected or sealed at the window vent kit or the unit's rear port.
FIX Power the unit off. Check both ends of the exhaust hose. Ensure the hose is pushed completely onto the rear port until it clicks. At the window bracket, ensure the hose adapter is fully twisted and locked into place. The window slider must be closed snugly against the bracket. Run the unit in Cool mode, not Fan mode.
IF THAT DIDN'T WORK The unit may have lost refrigerant due to a leak. This requires a professional technician. Do not attempt to recharge it yourself.
HEADS UP If the room is very humid, the unit may cycle the compressor off to dehumidify. This can feel like 'just air' for short periods. Check if the compressor (the lower, heavier noise) kicks in after a few minutes.