To try and resolve the issue, please ensure the following:
1. That the paper size selected in the printer driver (if printing from the computer), or on the printer itself (if making photocopies) is A4, B5, A5, Letter, or envelopes. If another paper size is selected, the printer will attempt to feed from the upper cassette tray.
2. That the paper path of the printer is clear so that the paper can feed smoothly. To do this, please perform a roller cleaning on the unit by following the steps located here.
3. That the paper is secured in the paper tray by ensuring the paper guides are snug against the paper.
If you still experience difficulty, we ask that you please call 1-866-261-9362, Monday - Friday 10:00 a.m. - 10:00 p.m. ET (excluding holidays) and a Canon technical support representative will be happy to help. There is no charge for this call.