An air filter’s job is to prevent dirt, dust, and other airborne particles from entering the air conditioner, and so, the air filter tends to get very dirty. A dirty air filter, in turn, blocks air flowing into the air conditioner and can even lead to a complete shutdown.
Remove the air filter and clean it using a soft brush. Check if doing so fixes the problem, and your AC starts cooling. If not, you need to call an expert for AC repair in Poway, CA.