I'll move this for you.
Is your Canon camera the Canon XA10? If so, does it not present the MXF format?
Premiere Elements is not compatible with MXF. But, you seem to have gotten the Canon footage into the project if you are at the stage where you are exporting the Timeline containing it. So, please clarify on the point of MXF format or not.
The bottom line may be for you to export that Timeline to a file saved to the computer hard drive. And, then upload that file from the computer hard drive to YouTube at the YouTube web site. Have you tried that for troubleshooting purposes?
The Samsung video (cell phone) is typically characterized by a variable frame rate. When you were in the Edit area of the program, did you run into any audio out of sync issues when you played back the rendered Timeline in the Edit Mode monitor?
Please review, try the upload at the YouTube web site, and then let us know the outcome so that we can consider what next if necessary.