Hello, wondering if anyone has insight on why this happened... I noticed that the blue LED wasn't lighting up when I hit the button. I had a 3 ohm carto on the IPro and it was firing fine, only the blue LED wasn't lighting. I took the carto off and hit the button and still no blue LED. I figured the batteries were low so I installed freshly charged batteries and got the same result- no blue LED. I then put the original batteries back in and continued to vape. I switched over to a 2.2 ohm carto and vaped a little while. Now the blue LED is working again, on either carto. - Any ideas? Thanks.