There was paper jam happened at first. After I got the paper out, it's not going to the feed the paper properly. And then I tried to clean the roller following this: https://support.usa.canon.com/kb/index?page=content&id=ART142302.
I have done until this: Hold down the Stop button until the Alarm lamp flashes orange seven times, then release it immediately. The machine starts cleaning. The cleaning will be complete when the paper is ejected.
It happend that only 1/10 of the paper is fed in and stopped very soon so the paper is not ejected. Now I can't print anything with my printer. It's only 2-3 months old. Can some experts here please help me? Thank you very much!