Hi, i have a provari, I have 2 protanks, both have been working fine for months, now for some reason one of my tanks suddenly has developed a fault where there is no airflow when it is attached to the provari (but has fine airflow when not attached). I have tried many heads, with no change. My other protank works fine, cant figure it out. I have tried loosening it a bit, loosening the head a bit, but no luck. Anyone had this issue or have any recommendations?