The Strategy for Office add-in does not load when using Microsoft Office online in Internet Explorer 11.
An update to Microsoft's Office API can cause issues with Internet Explorer 11 that prevents starting the Strategy for Office add-in. We are currently in touch with Microsoft regarding a fix for this issue. In the meantime, you can use the workaround in the next section.
The user/administrator needs to change the script being used to load the Microsoft Excel API.