Check iframe compatibility and troubleshoot blank device screens

A website can load normally in a browser and still refuse to appear inside an iframe. This is controlled by the remote website, not by Responsive Mockup Generator.

Common blocking headers #

• X-Frame-Options: DENY blocks every external frame.
• X-Frame-Options: SAMEORIGIN allows frames only on the same origin.
• A Content Security Policy with a restrictive frame-ancestors directive can block selected domains.

Use the compatibility check #

Enter the website URL in a client project and choose Check iframe compatibility. A positive result improves confidence but cannot guarantee every page or browser will behave identically.

Troubleshooting checklist #

1. Use the final HTTPS URL, including the correct path.
2. For YouTube, use an official youtube.com/embed/... URL rather than a regular watch page.
3. Check the browser console for frame or Content Security Policy errors.
4. Test in a logged-out private window to exclude administrator-only behavior.
5. Try a known iframe-friendly public page to verify the generator itself.

The plugin does not and must not bypass a remote site’s security policy. Ask the website owner to permit your domain or use a stored featured image instead.