AJAX using HTTP instead of HTTPS

My AJAX request is using HTTP even though the request is being made on the page using HTTPS. Any idea why this is downgrading to HTTP?

Here's my AJAX request:

$(function() {

  // Update section options whne course is changed
  $('#id_new_course').change(function() {

    // Get selected coursenum
    var val = $(this).val();
    var sect_input = $('#id_section');

    // Disable #id_section when no course is selected
    if (val == '') {
      sect_input.empty();
      sect_input.prop('disabled', true);
    } else {
      // Get list of sections for selected course and update #id_section options
      $.ajax({
        url: '/account/support_dashboard.get_course_sections/' + val + '/',
        dataType: 'json',
        success: function(data) {
          // Empty options and add new ones to #id_section
          sect_input.empty();
          $.each(data, function(value, key) {
            sect_input.append($('<option></option>').attr('value', value).text(key));
          });
          sect_input.prop('disabled', false);
        },
        error: function() {
          console.log('ERROR OCCURRED TRY AGAIN');
        }
      });//ajax
    }//if

  });

}); //ready

      

        
        
        
      

    

Here's the error output in my web console:

Mixed Content: The page at 'https://www.myeducator.com/account/support_dashboard/1027/993532704604577793/' was loaded over HTTPS, but requested an insecure XMLHttpRequest endpoint 'http://www.myeducator.com/account/support_dashboard.get_course_sections/915ba/'. This request has been blocked; the content must be served over HTTPS.

      

        
        
        
      

    

The javascript file is loaded over HTTPS:

Also, the actual ajax request comes out as HTTPS:

I also don't think it has anything to do with my webserver (nginx). I only have one rewrite command that redirects any raw subdomains to www.myeducator.com using the same request scheme:

server {
  listen 443 default_server ssl;
  server_name _;

  ...

  # the rewrite string
  rewrite ^ $scheme://www.myeducator.com$request_uri redirect;
}