Error in Internet Explorer "Only secure content is displayed"
|Progress® Telerik® Reporting
|HTML5-based Report Viewers
"Only secure content is displayed"
If you use an IFRAME element to load the page with the HTML5 Viewer, and all requests are issued over HTTPS, the error can occur due to a left link that uses HTTP.
The issue can be detected by running the page in Internet Explorer with opened Console (F12 Developer Tools). In the error logs you will see a message like the following:
HTTPS security is compromised by http://kendo.cdn.telerik.com/2015.3.930/styles/kendo.common.min.css
This will hint you which CSS/JS files are requested over HTTP.