The "Bad Request 400" error in Nginx when running Django with Gunicorn usually indicates an issue with the HTTP request that Nginx is forwarding to Gunicorn. Here's a breakdown of common causes and how to troubleshoot them:

1. ALLOWED_HOSTS Setting in Django:

• Problem: Django's ALLOWED_HOSTS setting is a security measure that prevents requests with unknown host headers from being processed. If Nginx forwards a request with a host that's not listed in ALLOWED_HOSTS, Django will return a 400 error.

• Solution:

  • Open your Django project's settings.py file.
  • Add your domain name or IP address to the ALLOWED_HOSTS list. For example:
  Python

   

  ALLOWED_HOSTS = ['yourdomain.com', '127.0.0.1', 'localhost']
  

  • If you're unsure