Shortly before the start of the fall 2013 semester, several web browser makers released new versions of their web browsers, new versions that deliberately established new and more restrictive rules for links, embedded items, and other web content. As a result, web browsers now decline to open or load web content that worked in the past.
What is being blocked is called Mixed Content. This is content that is non-secure web content on a secure web page. Things like links, scripts, external style sheets and eventually images, embedded audio and video.
This is being done to provide a safe and secure environment. It is a known issue for us with FIreFox in D2L.
The best way for us to address this is to share a nicely done tutorial from Millersville University. https://wiki.millersville.edu/display/d2ldocs/understanding+mixed+content#Understandingmixedcontent-Asaninstructorinoneormorecourses%2ChowmayIfixmycontent%3F
One key point is that in IE we tend to not see any issues and in most other browsers there is a “Shield” that can be clicked on to allow the content to be viewed. Safari does not block mixed content.
For more information, check out the info from Millersville University. (Special thanks to them for their work on this tutorial.)