Atomizer break in period.
When atomizers are produced at the factory, a primer liquid is place on the wick to keep it moist during transport. Some users have reported that it has a very unpleasant taste. It is important to know that this is normal, and once the atomizer is broken in with your favorite e-juice, it will be pleasant vaping! Many people will drip 1 or 2 drops directly into the wick of the atomizer to expedite the break in time.
In addition, the atomizer may not produce that fog like vapor in the very beginning. The more you use it, the better the performance.
In summary, when you get your atomizer, drip a few drops of e-juice directly on to the wick. Ensure your cartridge is full and vape away. If the performance seems poor, continue to vape – it should improve with further use.