Receiving a 400 Bad Request while accessing your own Django application can be frustrating.

This error in Django indicates that the server was unable to process the request sent by the client due to invalid syntax.

Here at Bobcares, we often receive requests on fixing Django errors as a part of our Server Management Services.

Today, let’s see how our Support Engineers fix this error.

How we fix Django 400 bad request error?

Now, let’s see how our Support Engineers go fixing this error.

1. Correct the Invalid syntax

Recently, one of our customers approached telling us that the Django server was running fine with DEBUG = True. But, when the DEBUG is set to False in the settings file, then the server will stop and throw the below error in the command prompt:

CommandError: You must set settings.ALLOWED_HOSTS if DEBUG is False.

After changing ALLOWED_HOSTS to,["http://127.0.0.1:8000",] in the browser, the customer received the below error

Bad Request (400)

Our Support Engineers started troubleshooting the error by setting the ALLOWED_HOSTS list to fully qualified hostnames.

We didn’t set the URL in it. And, omitted the port and the protocol.

ALLOWED_HOSTS = ['127.0.0.1', 'localhost']

Since our customer was using 127.0.0.1, we added localhost to the list too.

We can also use * to match any host:

ALLOWED_HOSTS = ['*']

Finally, this fixed the error.

2. Remove the Corrupt extensions in Django

We received another error from one of our customers. The error was as below.

[09/Nov/2010 00:31:53] "GET /acq/ HTTP/1.1" 200 1393
[09/Nov/2010 00:31:53] code 400, message Bad request syntax ('\x16\x03\x00...')
?????????...." 400 -???8 .....?????
[09/Nov/2010 00:33:39] "GET /acq/ HTTP/1.1" 200 1393

Our Support Engineers started troubleshooting this error by clearing the cache.

Then, we tried uninstalling all the extensions.

That did the trick. After the uninstallation, the error disappeared. We finally found that the trouble was with the Secure Sites extension which lets to access a secure website.

Finally, we fixed this error by adding localhost to “Assumed no secure version exists” within the extension’s options.

3. Clearing the cache to fix 400 bad request error

The cache can also create problems. So we simply suggest our customers clear the cache and try checking if the error disappears.

Also, we suggest logging out from the framework and ask to login again and see if it works because the cached cookies will have the old login session.

[Need further assistance with Django errors? – We’ll help you]

Conclusion

In short, the Django 400 bad request is caused due to many reasons which include incorrect syntax, corrupt extensions, incorrect URL, and so on. Today, we saw how our Support Engineers fix it.