Split air conditioner is not cooling well

Check that the air inlet and outlet of the unit
condenser and evaporator are blocked.
Check that doors and windows are open.
Check that the air filter is not clogged with dust.
Check that the deflector is not in the correct position.
Check that the fan speed is low.
Check that the set temperature is high.
Check if the environment has a large number of
people.
Check for excessive heat sources.
Check if the sun's rays are penetrating the environment