Error "You're accessing the development server over HTTPS, but it only supports HTTP"

I think you should create different settings.py ( base_settings.py, local_settings.py, production_settings.py). And in your settings.py do something like this:

import socket
if socket.gethostname()=="Raouf-PC":
    from local_settings import *

Change 'Raouf-PC' to the hostname of your PC.

P:S: I'm using Windows 10.

After doing that place the below data in your production_settings.py and save. Then clear your browser cache and visit your site in development server.

SESSION_COOKIE_SECURE = True
CSRF_COOKIE_SECURE = True
SECURE_SSL_REDIRECT = True

If the above doesn't suit your needs, then in your local_settings.py paste the below data, save and clear your browser cache and visit your site.

SESSION_COOKIE_SECURE = False
CSRF_COOKIE_SECURE = False
SECURE_SSL_REDIRECT = False

Note: at the beginning of production_setttings.py and local_settings.py put:

from base_settings.py import *

Your base settings should contain 'settings' that will be used both on local and production server so you won't be repeating it everytime.

P:S If my answer is accepted, I dedicate it to the good people on SO who have helped me in one way or the other. This is my first time of answering a question. I hope to do more in the future. :)

You probably have the setting SECURE_SSL_REDIRECT set to True

This setting should be False when running the development server

CORS_REPLACE_HTTPS_REFERER      = False
HOST_SCHEME                     = "http://"
SECURE_PROXY_SSL_HEADER         = None
SECURE_SSL_REDIRECT             = False
SESSION_COOKIE_SECURE           = False
CSRF_COOKIE_SECURE              = False
SECURE_HSTS_SECONDS             = None
SECURE_HSTS_INCLUDE_SUBDOMAINS  = False
SECURE_FRAME_DENY               = False

1. Put this settings at the end of your settings.py
2. Clear your browser cache and then run your project.