1300 — paper jam
Turn the printer off before you reach inside. Pull the sheet slowly with both hands, in the direction the paper was already travelling, never backwards, and never with tweezers or anything sharp. Check both ends, because a sheet often sits half in the rear tray and half in the output slot and the part you can see isn't the whole thing. A torn scrap left behind causes the next three jams, so it's worth looking twice.