Hello! Thank you for contacting JustAnswer.com; I am Russell H., an Expert here at JustAnswer.com, and I will do what I can to answer your question as well as it can be answered.
OK, I think you should first try (just to get it out of the way) a hard reset of the printer.
To hard-reset it in generic fashion:
Turn the printer OFF, when it is on, by suddenly and sharply unplugging it from the power source.
Also unplug it from the computer!
Leave it that way for 10 minutes.
Plug it back in.
Turn it on if it didn't turn itself on. Wait for it to initialize.
Try printing again.
Then, if that doesn't clear the error, you have to do this stuff:
A. open up the printer(after powering it OFF for safety) - all the hatches, all the doors, everything that can swing out or up. And also remove all the paper trays, and all the stacks of paper everywhere.
B. Look at everything (including the paper trays)... is there anything stuck anywhere? esp. in a sensor, esp. paper bits or dust. Is there anything broken anywhere? How about something (like, e.g. a swinging mini-lever or little switch-like thing, which might be a mechanical sensor) out of place, or jammed in an odd position? Correct what you find.
C. If your printer is an inkjet (rather than a laser printer), unplug it, with everything open, then turn it upside down (-don't do this with a laser, toner spills could happen inside and make things worse!-), and shake it - unless it's too heavy or you might drop it... in which case, get someone to help you, e.g. someone really big and strong.
If that eliminates or dislodges anything - paper bits, blocks of nameless hard stuff, or paper clips - then you may have cured the problem. Put the printer right-side-up, reattach all pieces and close all doors etc, plug it in, power it on, and see what it does.
Please tell me, by Reply To Expert, what you found out, and how things went. Thanks.