Air flowing into paint bottle not picking up



I have a new syphon airbrush and it worked perfect the first time I used it. I cleaned it and now while trying to use it air is flowing into the paint bottle and airbrush is not working. It actually is pushing paint out of the bottle. Have I done something wrong or is the airbrush defective?
What airbrush are you using?, you could have a blocked nozzle or in some cases there is an adjustable paint nozzle going from the paint bottle to the nose, if this is too far forward you'll be blowing in instead of sucking out, a photo would help immensely.