I am using a Provari 2.5 with a Kanger Protank and I've been adjusting the voltage between 4.0 and 5.0 (under 4.0 it doesn't activate so I've ruled out under 4.0) the Protank is 2.5ohms. While drawing the inhale my Provari shuts off mid draw. I've tried adjusting up and down the voltage. What the heck am I doing wrong?