Another thought came to mind last night, and I think someone else already mentioned it. You may have accidentally flooded the atty inside. I did this myself, which is why I thought to post a follow up. I had an otherwise good working one running out of a favorite juice last night. I deliberately vaped it nearly dry and then refilled with another flavor. I refilled it while watching tv. It was sort of dark and my precision with the dropper tip was not ideal. Plus I over-filled it by a little. It acted dead when I started trying to use it. I could hear it sizzling and it got hot, but no vapor. I came --><-- this close to tossing it and grabbing a new one. But the tv show was riveting and instead I just sat there trying it over and over. Eventually it came back to life. It probably took 10-15 minutes of hitting it hard before it produced anything, and another 10 before it was producing acceptable vapor.
Flooded the crap out of it from user error.