First things first, start by checking your remote.Mostly if your AC is not cooling, the units need service, cleaned, and then checked for gas pressure. If Gas pressure is low then, Gas top-up needs to be done.
Reason 2 Another reason for your AC not cooling could be a bad or defective capacitor. The compressor will not start if the capacitor is defective
Reason 3 Problem with the outdoor unit's Fan Motor.