First thing to do is isolate the problem. Usually it will be in one of two places - the air tip or the air valve. Unscrew the air tip/head and press the trigger. If the airflow is sufficient, then it may be a blockage in the head. This may be dried paint or other debris which has found its way in there. If the airflow is not sufficient it would suggest a blockage in the air valve itself.
If you are confident enough, you may carefully disassemble the air valve to inspect, otherwise make arrangements with Badger to return the airbrush for servicing. Your Badger carries a lifetime labour warranty, so if it should just be a matter of shipping cost and your airbrush should be good as new.
Also note that when using a propel can, pressure will drop as you progress in a painting session. As "air" is released from the can, it will begin to chill - eventually it will chill to a point where the pressure will fall to an unusable level, even if it feels like there is plenty of liquid propellant. When it returns to room temp, full pressure will return. You can assist this by standing the can in a basin of warm (not hot) water.