Hi! Im building a portfolio site that embeds my projects in iframes. Multiple projects randomly returns 403 Forbidden when embedded on my main site What I’ve done: Tried using a custom domain and original .vercel.app domain Added Content-Security-Policy header in vercel.json: Disabled Ve…

Glad it was resolved, and thanks for confirming. If the issue is fully fixed now, could you mark the topic as solved or close it? That should make it easier for others who run into the same 403 iframe issue to see that it was resolved by the recent 403 fix.

Thanks for sharing! Seems like there are no answers yet

Hi Vignesh, Since this happens specifically when the project is embedded in an iframe, I would separate two possible causes: The iframe is being blocked by headers/browser policy. Vercel is returning a real 403: Forbidden before the page loads. The quickest way to narrow it down is to open…

Hi! It got resolved with the recent 403 fix but thanks for the thorough help again!

Random 403 Forbidden errors when embedding external v0 domain in iframe

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steliospne (Steliospne) May 11, 2026, 10:46am 3

You can follow this thread, we all have related issues.

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Random 403 Forbidden errors when embedding external v0 domain in iframe

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