I had this same problem too. Turns out it was the juice. If you dont wanna buy coils every 2 days, might I suggest getting a kayfun lite + and learn to rebuild. It's very easy and way cheaper than buying those crappy little protank atomizer heads. A roll of wire and a bag of cotton balls will last you forever.
This is my new years resolution! Rebuilding nice attys 8) My local dealer is going to have classes in the near future, so Im pumped for that!