A new feature in ITMS 8.8 is to Import software from the Microsoft Store. In the SMP Console go to Manage > Software and then select Add Software > Import Microsoft Store Package and this will take you to the Microsoft Store Import Wizard.
Your organization is blocking this feature from downloading from the Microsoft Store. What URL is it downloading from?
ITMS 8.8
You will want to Wireshark this application to gather all of the URL's needed.
As of publication of this KB article the URL's below are being used, when searching for packages to download:
storeedgefd.dsx.mp.microsoft.com
ctldl.windowsupdate.com
To Download packages:
displaycatalog.mp.microsoft.com