Oki C9300 - paper keeps

your getting a 383 paper jam, find paper in two different places.
See if it's a duplex related problem. print single sided documents, if that works, try printing two sided documents (it'll be the duplexer) if it only fails while printing duplex.

Also, check the back door. Make sure the back exit tray is closed all the way.

You can also have a paper jam in the duplex unit (open the front door), the duplex unit slides out the front. You can easily remove the duplex unit and run the printer without it.

Have you check out setting for printer: setting in the print driver, Under the General tab > Printing Preferences > Paper/Quality tab > Advanced > Printer features .. Make them default..
Also get updated for your Operating system and printer drivers from the website.
Power off printer, remove the toner then Clean all of them, berfore inserting toner clean the internal area with a Blower or vaccum cleaner. With a clean cotton cloth also and then, power it on-> check for print.