I just received 2 packs of the Nautilus Mini coils and tried them in my Provari. The first one is still working great and the second one in another Provari worked for awhile at around 3.6 or 3.7 voltage, and then I got an E-1 error on my Provari. So, I tried lowering the voltage to 3.4 and still got the error. I have no idea why I got the error. I popped in another coil, and it works as it should. The only thing I can assume is that it was a bad coil. I would like to know if this has happened with anyone else.