There are lots of reasons for this, and almost all of them will require help from a professional technician. Start by making sure your air filter is clean. If the filter was at fault, speed up the thawing process by turning your system off, then turning on the fan only—just make sure you switch the system settings back to normal after. Other possible causes are low refrigerant, a dirty evaporator coil, or a defective blower motor or relay. These would require further diagnosis from a ComfortMax professional.