This warning message occurs when items on the following web site (frames, images and other objects) are referenced in a non-secure manner (http). For example the page code might include an image or code that pulls from a non-secure URL.
Internet Explorer interrupts the download and displays a confirmation dialog whenever it detects the use of mixed content on a secure page.
To resolve this issue make sure that the page code does not pull data directly from a non-secure URL.
To check for insecure items, perform the following steps:
1. Access the web site with Internet Explorer
2. Click No to display non-secure items
3. Right-click on the body of the web page
4. Select View Source
To identify non-secure elements view the source code of the page and search for the text src="http://
This will then highlight elements on your page being loaded from a non-secure URL.
The source code (HTML) needs to be checked for NON SECURE tags. (i.e. <img src="http://www.mydomain.com/test.html...">) Ensure the following references are changed to https or a virtual directory.
Note: The webmaster should always be consulted prior to any adjustments made to a web site.
For more information, please refer to the Microsoft Support article: