Print an external page without opening it not working in Firefox

MDN
#1

I’m trying to print a PDF document without opening it. I found a guide on MDN that explains how this can be done.

  const handleClick = (
    event: React.MouseEvent<HTMLButtonElement, MouseEvent>,
  ) => {
    event.stopPropagation();
    event.preventDefault();

    const frame = document.createElement('iframe');

    frame.onload = () => {
      frame.contentWindow.print();
    };
    // frame.style.display = 'none';
    frame.src = docflow.primaryDocumentPdfUrl;
    document.body.appendChild(frame);
  };

In Chrome everything works well, but in Firefox an error occurs (see below).

Partitioned cookie or storage access was provided to
“http://localhost:3000/api/documents/5bf1c493-b8ce-4f82-9ee0-def28065c645/visualization”
because it is loaded in the third-party context and dynamic state
partitioning is enabled

enter image description here

Storage tab screenshot:

enter image description here

Guide is wrong or am I doing wrong?