Have run into an issue recently where two colleagues couldn’t load a SharePoint calendar – instead of the dynamic list with active links etc. it loaded with a flat image and was completely inactive.

SharePoint_Calender_Issue_1

This article explains exactly why that seems to be occurring

I don’t know if there is a SharePoint patch to resolve, but an easy fix is to add your SharePoint sites address to Internet Explorer as a Trusted Site

The calendar will then load ok:

SharePoint_Calender_Issue_2