A family of Microsoft presentation graphics products that offer tools for creating presentations and adding graphic effects like multimedia objects and special effects with text.
With this whole thing living in the cloud, there's no telling (at least from the Humble User seat, where we sit) what might have gone wrong.
At one point, though, I found that when PPT itself couldn't download an icon directly, I could copy the the URL it complained about in the error message and plug that into the browser (Firefox again) and IT was able to pull down the image.
Whether that was due to a bug in PPT or just a temporary outage that was corrected by the time I tried it in Firefox .... impossible to say from here in Humble Userland.