"PDF could not be loaded" appears when a URL is used that responds with a 302 redirect. It works fine for the image component.
Yes! We tried to troubleshoot this, and found out that the PDF component does not work with redirects - causing us headaches!
Thanks @ousamp @oles for this feedback! I've surfaced both of your interest in this on an internal request for our eng team. Will update here if/when this is prioritized.