WebFilter blocking downloads

I am trying to install a Google Chrome extension, but my web filter is blocking the download, even after allowing the category:

 URL: https://chromewebstore.google.com/

Extension: Microsoft Single Sign On

Category: Freeware and Software Downloads

Risk Level: Trustworthy

Group: Bandwidth Consuming

The website loads normally, but when I click to download the extension, I get an error message.

I removed the web filter and it worked. I believe it is in another category, but I don't know which one.