This package appears to have a custom/proprietary license agreement, and ProGet cannot be automatically determine the license type. You'll need to assign a license type to the URL to allow or block packages with this license.
To install KB2533623 from the command line, run the following command:
choco install KB2533623 --version 2.0.0 --source https://choco.csdesiles.qc.ca:80/nuget/ChocoCSI/