Fix: An add-on for this website failed to run.
… Check the security settings in Internet Options for potential conflicts.”. You may receive this warning message while attempting to load any web page uses IE ActiveX plug-ins like Flash, Java/JRE, Silverlight, etc, as shown in below example screenshot.
As reported by the IE, the most probable cause for this is that you have High IE Security settings as shown below:
Set appropriate IE Security settings so that ActiveX controls are allowed to be run without prompts. More simple you can reduce your IE security settings to Meduim-High level.