Kyocera FS-C1020MFP - Manual (Page 133)

Load the new paper stack print side up.
Make sure paper is not stacked higher than the upper limit (upper line) marked inside the tray.
Slide the guides inward until they are flush against the paper's sides.
Make sure the paper is not stacked higher than the projection on the side paper guides.
Check there are no gaps between the paper and the paper guides; both side and front
end paper guides.
If there is a gap between the paper and the front end paper guide, as in the example below, the paper
might not feed in correctly.