Firefox Can’t Open This Page in an iframe

What it means

Why it happens

1. 01

   X-Frame-Options: the console says the load “is denied by “X-Frame-Options“ directive set to” deny or sameorigin.

2. 02

   CSP frame-ancestors: the console line starts with Content-Security-Policy: and names the directive.

Check the page

Fix it if you own the site

location / {
  proxy_hide_header X-Frame-Options;
  add_header Content-Security-Policy "frame-ancestors 'self' https://your-site.com" always;
}

If you do not own the site

1. 01
   Use the official embed URL

   YouTube, Google Maps, Calendly, and others give a special embed link that allows frames.

2. 02
   Link out instead

   Open the page in a new tab with a normal link, or show a preview card that links to it.

3. 03
   Ask the owner

   Ask them to add your site to frame-ancestors. Send them this page.

Sources

• Firefox source: certError.ftl
• Firefox source: security.properties
• Firefox source: csp.properties
• MDN: X-Frame-Options header