title: Django enctype=multipart/form-data on localhost returns white screen
body: <p>I am running django on a pipenv virtual machine on my MacBook on localhost:8000. I created a django form to upload an image with enctype=multipart/form-data.</p>
  
  <p>When clicking on submit, on all browsers, I get a white page. Checking the browsers network status, its a 400 error, and in Firefox I get:</p>
  
  <p><code>The character encoding of the plain text document was not declared. The document will render with garbled text in some browser configurations if the document contains characters from outside the US-ASCII range. The character encoding of the file needs to be declared in the transfer protocol or file needs to use a byte order mark as an encoding signature.</code></p>
  
  <p>When removing the enctype, everything works fine - but of course the image isn't uploaded.
  The error seems to occur before any data manipulation on my side.</p>
  
  <p>On a remote development server, everything works fine with and without encoding - so it seems to be related to my development environment. </p>
  
  <p>Unfortunately I can't find any hints on why this error occurs. Does anybody have a hint or an idea on how to solve this?</p>
  
  <p><strong>More Information</strong></p>
  
  <ul>
  <li>Macbook Pro Catalina 10.15.3</li>
  <li>Django 2.2</li>
  <li>Running with the django internal server (manage.py runserver)</li>
  </ul>
  
  <p><strong>Update</strong></p>
  
  <p>The same issue occurs on the django admin edit page ( <a href="http://localhost:8000/admin/auth/user/1/change/" rel="nofollow noreferrer">http://localhost:8000/admin/auth/user/1/change/</a> ). I noticed there is a multipart encoded form as well. Submitting this results in the same error.</p>
  
  <p><strong>Update 2</strong></p>
  
  <p>The issue has been found. I have been installing the new app with the requirements.txt of our project and found that the library <code>channels</code> was outdated. </p>
  
  <p><em>Thanks for your help!</em></p>