HELP-PDF won't load in `<ifile>` in CodePen

I would like to load a PDF into an <ifile> on CodePen, but it will not load. Please see , line 26 of HTML editor, replace srcdoc with src to see that it does not work. (I used srcdoc to get the URL into the <ifile> area.) This is my Game of Life project.

This works fine locally in Safari and Firefox.

Thank you