Internet Explorer has been discontinued by Microsoft. It is no longer being supported or updated by Microsoft.
You will need to upgrade to Microsoft Edge.
The green lock icon will properly display in the browser address bar when viewing your website in the new Microsoft Edge browser.
To read more about this, see the following articles.
- Internet Explorer is dead: Microsoft to stop supporting early versions today as it begins to kill off browser
Death To Internet Explorer: Microsoft To Retire All Versions Under IE11 In January (2016)
After Jan. 12, 2016, Microsoft will no longer provide security updates or technical support for older versions of Internet Explorer," says Microsoft. "Security updates patch vulnerabilities that may be exploited by malware, helping to keep users and their data safer. Regular security updates help protect computers from malicious attacks, so upgrading and staying current is important.