> I was thinking maybe I moved the printer and it is not level?

Unlike the inkjet where it shines a little LED through the cartridge (covering with black electrical tape makes it think it's always full), laser toner I think has an id chip on the cartridge and the printer just maintains an internal counter as to guess when it'll run out. Reset that, and make sure the option is turned off that stops it continuing to print once low (networked models have a webpage you can go to to turn these from stop to just warn).

That's actually great information because it has been driving me crazy. I put in a brand new cartridge and it still complains. I assumed it was non-OEM BS.

You could try to shake the toner cartridge a bit from side to side. Try to make the toner even. It might help, it might not.

No point in doing this unless the prints themselves are fading out. Doing it with a full aftermarket cartridge is just asking for a mess.