Localhost refused to connect
on port 3000
Your browser returned ERR_CONNECTION_REFUSED while reaching http://localhost:3000. This means the server is either not running, bound to a different interface, or blocked by a firewall.
Error code
// Chrome DevTools → Console
GET http://localhost:3000/ net::ERR_CONNECTION_REFUSED
// Node.js server log
Error: listen EADDRINUSE: address already in use :::3000
at Server.setupListenHandle [as _listen2] (node:net:1872:16)
at listenInCluster (node:net:1920:12)
at doListen (node:net:2060:7)Root cause
Chromium returns ERR_CONNECTION_REFUSED when the TCP connection is actively rejected — meaning nothing is listening on the target port, or a firewall refused the handshake. With Node.js, this almost always pairs with EADDRINUSE in the terminal, telling you a previous process is still bound to the port.
Resolution steps
Work through these in order — each one builds on the previous.
1 Check if the dev server is actually running
Check if the dev server is actually running
Open your terminal and confirm your framework is listening. Look for a line like "ready on http://localhost:3000".
2 Find and kill the conflicting process on port 3000
Find and kill the conflicting process on port 3000
Use lsof to identify the PID hogging the port, then kill it cleanly.
# macOS / Linux
lsof -ti:3000 | xargs kill -9
# Windows (PowerShell)
Get-Process -Id (Get-NetTCPConnection -LocalPort 3000).OwningProcess | Stop-Process -Force 3 Verify the server binds to 0.0.0.0 (not just 127.0.0.1)
Verify the server binds to 0.0.0.0 (not just 127.0.0.1)
If you’re using Docker, WSL, or remote dev, the server must bind to all interfaces.
next dev -H 0.0.0.0 -p 3000
# or in code:
app.listen(3000, '0.0.0.0', () => console.log('ready')) 4 Check for firewall or antivirus blocks
Check for firewall or antivirus blocks
On Windows, allow Node.js through Windows Defender Firewall. On macOS, grant the terminal Full Disk Access on first run.
5 Restart the server and reload the browser
Restart the server and reload the browser
Hard-reload with Ctrl+Shift+R (or Cmd+Shift+R) to bypass cached failed connections.
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