If you are trying to Vape Oils and not e-Liquid then it is combusting and burning the wick and will not allow it to wick. Vaporizers are for e-Liquid and not OILS of any kind.
I'll put it this way. I have been prescribed somewhere between 100-200 cartridges. They have ALL "vaped" perfectly fine up until two weeks ago. One cartridge quit while it was half full. I bought my 6th pen tonight. That's not counting duplicates, because I've got 2 or 3 duplicates. And I can't get a single cartridge to work with a single vape device. Volt meter shows the devices are putting out correct output. I've done every single "normal" suggestion you can find on the Internet. I have searched this topic to the end of Google and back, and I can't find a single thing that works, nor a single instance where someone had the same issue.
I'm telling you, I was literally vaping one second, then it completely ceased. Nobody believes me except for my wife who can see it with her own eyes.