[Django]-CommandError: You must set settings.ALLOWED_HOSTS if DEBUG is False

Try

ALLOWED_HOSTS = ['*']

Less secure if you’re not firewalled off or on a public LAN, but it’s what I use and it works.

EDIT: Interestingly enough I’ve been needing to add this to a few of my 1.8 projects even when DEBUG = True. Very unsure why.

EDIT: This is due to a Django security update as mentioned in my comment.

Your solution might be to add the original IP and/or hostname also:

ALLOWED_HOSTS = [
  'localhost',
  '127.0.0.1',
  '111.222.333.444',
  'mywebsite.example']

The condition to be satisfied is that the host header (or X-Forwarded-Host if USE_X_FORWARDED_HOST is enabled) should match one of the values in ALLOWED_HOSTS.

Make sure it’s not redefined again lower down in your settings.py. The default settings has:

ALLOWED_HOSTS = []

From documentation:
https://docs.djangoproject.com/en/1.10/ref/settings/

if DEBUG is False, you also need to properly set the ALLOWED_HOSTS
setting. Failing to do so will result in all requests being returned
as “Bad Request (400)”.

And from here:
https://docs.djangoproject.com/en/1.10/ref/settings/#std:setting-ALLOWED_HOSTS

I am using something like this:

ALLOWED_HOSTS = ['localhost', '127.0.0.1', 'www.mysite.com']

Use this:

ALLOWED_HOSTS =  ['localhost', '127.0.0.1']

If you work in PyCharm, check the Environmental variables for your Django server. You should specify the proper module.settings file

This works for me:

# SECURITY WARNING: don't run with debug turned on in production!
DEBUG = False

ALLOWED_HOSTS = ['localhost', '127.0.0.1']

If you are using PyCharm

This solution applies only if you are using a different settings.py and have environment variables set

I had the same issue, but in my case the issue was, I was using a different settings.py file than the default (and had commented out my whole original settings.py), though I had it properly configured in my manage.py but in PyCharm I had to configure it as well in my Environment Variables via:

Edit Run Configurations >> Environment Variables

I also experienced the same error and found it is happening due to settings file configuration change. You have to configured few things as below mentioned.

Try

In settings.py

ALLOWED_HOSTS = ['*']

In manage.py

def main():
    """Run administrative tasks."""
    os.environ.setdefault('DJANGO_SETTINGS_MODULE', '<your-project-name>.settings')

In asgi.py

os.environ.setdefault('DJANGO_SETTINGS_MODULE', '<your-project-name>.settings')

In wsgi.py

os.environ.setdefault('DJANGO_SETTINGS_MODULE', '<your-project-name>.settings')

In my case I had split out my settings.py into base.py and development.py in a settings folder. It looked something like:

<name-of-your-project-app>/
├── __init__.py
├── asgi.py
├── settings
│   ├── __init__.py
│   ├── base.py
│   └── development.py
├── urls.py
└── wsgi.py

The problem was much bigger than ALLOWED_HOSTS=… because none of the settings were recognized by python manage.py runserver.

The fix was to configure the DJANGO_SETTINGS_MODULE by running

export DJANGO_SETTINGS_MODULE=decoupled_dj.settings.development

in the command line. I think this tells Django, ‘Hey look for my settings in the development.py‘

So in my main directory in my django project, I had a two directories that had the same name so I deleted the settings folder I had and kept the settings.py file that comes with django.

What I had originally

<name-of-your-project-app>/
├── __init__.py
├── asgi.py
├── settings
│   ├── __init__.py
│   ├── base.py
│   └── development.py
├── settings.py
├── urls.py
└── wsgi.py

What I had afterwards

<name-of-your-project-app>/
├── __init__.py
├── asgi.py
├── settings.py
├── urls.py
└── wsgi.py

Try

# SECURITY WARNING: don't run with debug turned on in production!
DEBUG = True

ALLOWED_HOSTS = ['*']

A value of ‘*’ will match anything; in this case you are responsible to provide your own validation of the Host header.

I had set ALLOW_HOSTS, INTERNAL_IPS and DEBUG=TRUE

but still got this error.
my problem was i had created a python package which its name
was ‘settings’ in main app.
and that package name interfered with ‘settings.py’ file.

Make sure the name of the directory is the same that you are mentioning in the INSTALLED_APPS. These are the solution to errors sometimes.

Faced the same error when using a .env file in development in a local setup on my computer which I didn’t copy on the production server. As soon as I added the .env file on the production server the error was resolved. I have also added the server’s IP Address to the allowed_hosts list on the settings file.

You are getting this error because settings.py does not recognized by Pycharm correctly. Therefore you must specify your settings.py file in Preferences.

Go to: Preferences -> Languages & Frameworks -> Django ->

1. Enable Django Support
2. Set Django project root to your main project folder
3. Set Settings to your main_project/your_app/settings.py
4. Set Manage script to your main_folder/manage.py

I also experienced this cmderror. After trying all the answers on here, I couldn’t still figure out the problem, here is what I did:

1. Cd into the project directory. e.g cd project-dir
2. I migrated. e.g python manage.py migrate
3. I created a super user. e.g python manage.py createsuperuser
4. Enter the desired info like username, password, email etc
5. You should get a "super user created successfully" response
6. Now run the server. E.g python manage.py runserver
7. Click on the URL displayed
8. The URL on your browser should look like this, 127.0.0.1:8000/Quit
9. Now edit the URL on your browser to this, 127.0.0.1:8000/admin
10. You should see an administrative login page
11. Login with the super user info you created earlier on
12. You should be logged in to the Django administration
13. Now click on "view site" at the top of the page
14. You should see a page which shows "the install worked successfully….. Debug = True"
15. Voila! your server is up and running

Just simply comment out the line: ALLOWED_HOSTS = […]