"Why is my AC blowing hot air?" is one of the most common HVAC questions homeowners search for, and the honest answer is that it depends. Sometimes the fix is a thermostat setting. Sometimes it's a failed compressor.
Start with the easy checks: thermostat, air filter, circuit breaker, and outdoor unit. If those don't solve it, you're probably dealing with a refrigerant leak, a frozen coil, an electrical failure, or something else that needs a technician.