Django csrf verification fails after switching off https - django

Question

I am using Django 1.7.1 , I made a single change outside of my django web app , i.e switched off https inside nginx since my django webapp moved within the company firewall.
I made no other changes to the webapp , like in any of the django code: I am testing the webapp access via the company vpn.
The home page , which is a form loads fine when I go to http://mywebapp.mycompany.com.
Now , When I hit submit. I see the CSRF verification failure with a reference to https://mywebapp.mycompany.com! as detailed below. I even get the error in incognito mode to rule out any old cache issues.
I wanted to know the source of the error and feel it is outside of my webapp and within some vpn configuration/ browser cache / some other cache.
I have checked the possible reasons for CSRF failure given in the django message , and am not doing any of those "bad" things.
Any ideas on how to troubleshoot this. I want to know whether this is a VPN config problem , an nginx config problem or a django "best practices" problem.
Forbidden (403)
CSRF verification failed. Request aborted.
Help
Reason given for failure:
Referer checking failed - http://mywebapp.mycompany.com/ does not match https://mywebapp.mycompany.com/.
In general, this can occur when there is a genuine Cross Site Request Forgery, or when Django's CSRF mechanism has not been used correctly. For POST forms, you need to ensure:
Your browser is accepting cookies.
The view function uses RequestContext for the template, instead of Context.
In the template, there is a {% csrf_token %} template tag inside each POST form that targets an internal URL.
If you are not using CsrfViewMiddleware, then you must use csrf_protect on any views that use the csrf_token template tag, as well as those that accept the POST data.
You're seeing the help section of this page because you have DEBUG = True in your Django settings file. Change that to False, and only the initial error message will be displayed.
You can customize this page using the CSRF_FAILURE_VIEW setting.
I am not doing any of these. My form uses :
<form role="form" action={% url "sequence_input" %} data-persist="garlic" data-destroy="false" method="post" enctype="multipart/form-data">{% csrf_token %}
The calls to the form are using RequestContext:
return render(request,'sequence_input_form.html',{'form':form})
And I have the following context processors:
TEMPLATE_CONTEXT_PROCESSORS= ("django.core.context_processors.static",
"django.contrib.auth.context_processors.auth",
"django.core.context_processors.debug",
"django.core.context_processors.i18n",
"django.core.context_processors.media",
"django.core.context_processors.tz",
"django.contrib.messages.context_processors.messages",
"django.core.context_processors.request",)
My Nginx conf indicating commented lines.
server {
listen 80;
listen [::]:80 ipv6only=on;
#listen 443 default ssl;
charset utf-8;
# Make site accessible from http://localhost/
server_name [my server ip];
#if ($ssl_protocol = "") {
# rewrite ^(.*) https://$server_name$1 permanent;
#}
#if ( $scheme = "http" ) {
#return 301 https://$server_name$request_uri;
#}
#ssl_certificate /home/mywebapp/mywebapp/mywebapp_cert.crt;
#ssl_certificate_key /home/mywebapp/mywebapp/mywebapp_key.key;
#ssl_certificate_key /home/mywebapp/mywebapp/harijay/mywebapp_webhop_org.key;
location / {
uwsgi_pass django;
include /home/mywebapp/mywebapp/uwsgi_params;
uwsgi_read_timeout 60000;
root /home/mywebapp/mywebapp;
#index pam_lister/templates/sequence_input_form.html;
# First attempt to serve request as file, then
# as directory, then fall back to displaying a 404.
#try_files $uri $uri/ =404;
# Uncomment to enable naxsi on this location
# include /etc/nginx/naxsi.rules
}
location /static {
autoindex on;
alias /home/mywebapp/mywebapp/static/;
}
}