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Subject: Facebook crawler (facebookexternalhit) receiving 403 from Vercel deployment

Domain: www.jsvisualizer.bytefront.dev

Description:

Facebook’s crawler (facebookexternalhit) is receiving 403 responses from my Vercel deployment. Other crawlers return 200 successfully.

Troubleshooting completed:

  • Manually curling the domain with the facebookexternalhit User-Agent returns 200

  • Facebook’s Sharing Debugger tool returns 403

  • The block appears to be IP-specific, affecting Meta’s datacenter IP range (AS32934)

Firewall configuration:

  • Firewall is enabled on the project

  • A bypass rule exists for the facebookexternalhit User-Agent, but it doesn’t prevent the block

  • Bot Protection with managed rules is enabled

Request: Please investigate if Meta’s IP range (AS32934) is being incorrectly flagged or blocked at the infrastructure/edge level, and review edge logs to confirm the exact reason for the 403 responses.

2

The domain troubleshooting guide can help with most custom domain configuration issues. You might be able to use that guide to solve it before a human is available to help you. Then you can come back here and share the answer for bonus points.

You can also use v0 to narrow down the possibilities.