django error：DisallowedHost: Invalid HTTP_HOST header: ''. You may need to add u'' to ALLOWED_HOST

The error log is straightforward. As it suggested,You need to add 198.211.99.20 to your ALLOWED_HOSTS setting.In your project settings.py file,set ALLOWED_HOSTS like this :

ALLOWED_HOSTS = ['198.211.99.20', 'localhost', '127.0.0.1']

For further reading, Read from here.