Matt,
Pop the cap off of the cart and try to look straight down the barrel of the atomizer/wick. Are you able to see straight through? If not, the wick could be pinched or there could be something obstructing it, like a bit of silicone from the bottom plug.
Try blowing through the cart in short puffs from the mouthpiece end, kind of like if you're shooting a spit wad from a pen tube. If that doesn't clear it, you can try fishing a straightened paper clip through. You can also try to rinse and dry it, as that process moves a lot of fluid and air through the cart.
If you don't feel like monkeying with it, toss it. They're inexpensive enough that you don't need to feel too guilty about pitching it.
-HB