Fix Nginx Not Connecting to Gunicorn (Connection Refused)

If you're seeing errors like:

• connect() failed (111: Connection refused)
• Nginx returns 502 Bad Gateway
• Your Django app is not reachable

👉 Then Nginx cannot connect to Gunicorn.

This guide will help you identify and fix the issue step-by-step.

⚡ Quick Fix (Try This First)

Run:

sudo systemctl restart gunicorn
sudo systemctl restart nginx

Then reload your site.

👉 If still broken, continue below.

🧠 What “Connection Refused” Means

This error means:

Nginx tried to connect to Gunicorn, but nothing was listening

Common reasons:

• Gunicorn is not running
• Wrong port/socket
• Misconfiguration

🧪 Step-by-Step Diagnosis

Follow these steps carefully.

1. Check if Gunicorn is running

sudo systemctl status gunicorn

Expected:

• active (running)

If NOT running:

Start it:

sudo systemctl start gunicorn

2. Check Gunicorn logs

journalctl -u gunicorn --no-pager -n 50

Look for:

• Python errors
• Import failures
• Missing packages

3. Check what Gunicorn is listening on

If using TCP:

ss -tulnp | grep 8000

Expected:

LISTEN 0 128 127.0.0.1:8000

If using socket:

ls /var/www/myproject/

Look for:

gunicorn.sock

4. Check Nginx configuration

Open:

sudo nano /etc/nginx/sites-available/myproject

For TCP setup:

proxy_pass http://127.0.0.1:8000;

For socket setup:

proxy_pass http://unix:/var/www/myproject/gunicorn.sock;

👉 These must match Gunicorn exactly

5. Test Gunicorn directly

curl http://127.0.0.1:8000

If fails:

• Gunicorn is not running correctly

If works:

• Problem is Nginx configuration

6. Restart Nginx

sudo systemctl restart nginx

Then check your site again.

7. Check Nginx logs

sudo tail -f /var/log/nginx/error.log

Look for:

• connection refused
• no such file
• permission denied

🔥 Common Causes (and Fixes)

🔴 Gunicorn not running

Fix:

sudo systemctl start gunicorn
sudo systemctl enable gunicorn

🔴 Wrong port or socket

Mismatch between:

• Gunicorn bind
• Nginx proxy_pass

Fix by aligning both

🔴 Gunicorn crashed

Check:

journalctl -u gunicorn

Common issues:

• Syntax errors
• Missing dependencies

🔴 Socket file missing

Fix:

• Ensure Gunicorn creates socket
• Check working directory

🔴 Permission denied on socket

Fix:

sudo chown -R www-data:www-data /var/www/myproject
sudo chmod 755 /var/www/myproject

🔴 Firewall blocking connection

If using TCP:

sudo ufw allow 8000

🧠 Debugging Tips

Check listening ports

ss -tulnp

Check Gunicorn process

ps aux | grep gunicorn

Restart everything cleanly

sudo systemctl restart gunicorn
sudo systemctl restart nginx

✅ Quick Fix Checklist

• Gunicorn is running
• Correct port/socket configured
• Nginx config matches Gunicorn
• No errors in logs
• Permissions are correct
• Nginx restarted

🔗 Related Guides

• Fix Django 502 Bad Gateway
• Deploy Django with Nginx + Gunicorn
• Fix Gunicorn socket permission denied

❓ FAQ

What causes “connection refused”?

• Gunicorn not running
• Wrong port/socket
• Misconfiguration

Should I use socket or TCP?

• Socket → better performance
• TCP → easier debugging

Why does it work locally but not in production?

Because:

• Production uses Nginx + Gunicorn
• Local uses Django dev server

🎯 Final takeaway

“Connection refused” means:

Nginx cannot reach Gunicorn

Fix it by checking:

• Gunicorn status
• Ports/sockets *Configuration alignment

If you deploy often…

A repeatable, tested setup saves hours of debugging.