How to load content from CDN using react testing library

I am using NextJS with React Testing Library for component testing. I have a tinymce editor that loads from a CDN. When I tried to render my component which contains the tinymce component with React Testing Library, it failed. This is my Editor.jsx component:

"use client";

import { useRef } from "react";
import { Editor as TinymceEditor } from "@tinymce/tinymce-react";
import { init } from "./tinymceUtils";
import { Box } from "@mui/material";

function Editor() {

  return (
    <Box height="95vh">
      <TinymceEditor
        apiKey="my-api-key"
        onInit={(_evt, editor) => (editorRef.current = editor)}
        initialValue="<p>This is the initial content of the editor.</p>"
        init={init}
      />
    </Box>
  );
}

export default Editor;

And this is my test:

it("Should render <Editor /> with initial text", async function () {
  render(<Editor />);
  const editorTextarea = await screen.findByTestId(
    "tiny-react-editor",
    undefined,
    { timeout: 5000 }
  );

  const iframe = await waitFor(() => editorTextarea.querySelector("iframe"), {
    timeout: 10000,
  });

  console.log(iframe); //It logs null
});

So my test passes but the iframe is null and I cant get it. When I inspect the DOM on my browser, I see that there is a div with role="application" but can't load when I render my component through React Testing Library.