Sudden SSL Handshake Failure on Custom Domain (PR_END_OF_FILE_ERROR)

Help
1

Hello Vercel Community,

I’m experiencing a perplexing SSL issue that suddenly appeared without any configuration changes on my part.

The Issue

  • Custom domain (postello.io) suddenly shows “PR_END_OF_FILE_ERROR” during SSL handshake on ALL browsers
  • Vercel subdomain (social-content-generator-frontend.vercel.app) works perfectly fine
  • SSL Labs gives my domain an A+ rating with all tests passing
  • This happened suddenly with no changes on my end

Technical Details

  • Error: PR_END_OF_FILE_ERROR / Secure Connection Failed
  • Domain provider: Namecheap
  • DNS correctly pointed to Vercel
  • SSL Labs confirms SNI support is required
  • TLS 1.3 is correctly supported according to testing

Troubleshooting Steps Already Taken

  1. Removed and re-added the custom domain in Vercel dashboard
  2. Updated vercel.json with proper headers and redirects
  3. Verified DNS settings are correct in Namecheap
  4. Flushed DNS cache locally
  5. Tested in multiple browsers and devices
  6. Verified certificate shows as valid in Vercel dashboard
  7. Added proper HSTS headers

Questions for the Community

  1. Has anyone experienced a similar sudden SSL failure on custom domains?
  2. Are there known issues with Vercel’s edge network SSL handling for custom domains?
  3. What else can I check when the Vercel subdomain works but custom domain fails?
  4. Could this be related to recent changes in Vercel’s infrastructure?

Any insights would be greatly appreciated as this is blocking our production application!

Thanks in advance,
Ven

2

Hi @alwaysonplanb-gmailc, welcome to the Vercel Community!

Sorry that you faced this issue. Are you still facing this issue?

I’m able to access the website without any issues from the latest Google Chrome browser.

1 Like
3

Thanks for checking this one. On further troubleshooting the issue i found that it is the ISP and not the code or vercel related. I restarted my router and that fixed it.

Thanks again. This can be closed.

1 Like
4

This topic was automatically closed 7 days after the last reply. New replies are no longer allowed.