net::ERR_CONNECTION_REFUSED (This site can't be reached — refused to connect)
The browser reached the host but nothing was listening on that port.
Seen on:
JavaScript
Meaning
Locally it usually means the dev server isn’t running or is on another port; in production the web server or load balancer is down or the port is firewalled.
Common causes
- Dev server not running / wrong port
- Web server stopped
- Using http:// to an https-only port or vice versa
- Firewall rejecting the port
⚡ Quick fix
- Start the server and check its port
- Use the right scheme and port
- Check the server process and firewall
Detailed fix by platform
Linux
ss -ltnp | grep :3000
How to diagnose
- Server — Is it listening on that port?
- Scheme — http vs https?
🧠 Still stuck? Analyze your error
Paste the full message, response headers or stack trace — we'll detect the platform and point to the most likely cause.
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Last updated 2 Oct 2026