💬 Your Product Feedback Has Been Submitted 🎉

Thank you for taking the time to share your insights with us! Your feedback is invaluable as we build a better GitHub experience for all our users.

Here's what you can expect moving forward ⏩

• Your input will be carefully reviewed and cataloged by members of our product teams. 
  • Due to the high volume of submissions, we may not always be able to provide individual responses.
  • Rest assured, your feedback will help chart our course for product improvements.
• Other users may engage with your post, sharing their own perspectives or experiences. 
• GitHub staff may reach out for further clarification or insight. 
  • We may 'Answer' your discussion if there is a current solution, workaround, or roadmap/changelog post related to the feedback.

Where to look to see what's shipping 👀

• Read the Changelog for real-time updates on the latest GitHub features, enhancements, and calls for feedback.
• Explore our Product Roadmap, which details upcoming major releases and initiatives.

What you can do in the meantime 💻

• Upvote and comment on other user feedback Discussions that resonate with you.
• Add more information at any point! Useful details include: use cases, relevant labels, desired outcomes, and any accompanying screenshots.

As a member of the GitHub community, your participation is essential. While we can't promise that every suggestion will be implemented, we want to emphasize that your feedback is instrumental in guiding our decisions and priorities.

Thank you once again for your contribution to making GitHub even better! We're grateful for your ongoing support and collaboration in shaping the future of our platform. ⭐

Additional diagnostic result:

The application also returns HTTP 200 locally when I send the exact Codespaces forwarded hostname as the Host header:

curl -sS -o /dev/null
-w 'Local with Codespaces Host HTTP %{http_code}\n'
-H 'Host: fuzzy-space-fiesta-wvgv4xp6w6vg3gpxv-3000.app.github.dev'
http://127.0.0.1:3000/

Result:
Local with Codespaces Host HTTP 200

So the application accepts the forwarded hostname correctly. The HTTP 404 appears to occur in the Codespaces forwarding/access layer before the request reaches Next.js.

I'm experiencing a similar, but intermittent, issue with GitHub Codespaces.

Unlike the original report, I'm using a plain Node.js HTTP server (node server.js) rather than Next.js.

Environment and diagnostic results

• The server listens on port 3000, which is set to Private visibility.
• The forwarded URL sometimes works, but at other times the browser displays HTTP ERROR 404.
• I'm signed in to GitHub when this happens.
• curl -i http://localhost:3000/ returns HTTP/1.1 200 OK.
• A local request using the exact forwarded hostname in the Host header also returns HTTP 200.
• ss -ltnp | grep ':3000' confirms that a process is listening on port 3000.

Troubleshooting attempted

• Restarted the Node.js server.
• Stopped and recreated port forwarding for port 3000.
• Opened the forwarded URL directly from the Ports panel.

The issue still occurs intermittently.

I would prefer to keep the port Private rather than make it Public. Since this also happens with a plain Node.js server, could this be related to the Codespaces forwarding or access-control layer?

Has anyone experienced similar intermittent behavior, or found any additional diagnostics that can be performed while keeping the port Private?

Thank you for your help.

I used AI assistance to draft this comment; the diagnostic results are based on my own tests.