For hosted customers please raise a new case online and reference the title of this article.
For non-hosted customer, follow these steps:
From the Admin Tool Server, open Server Manager to configure Remote Desktop Services.
Go to Server Manager, then Remote Desktop Services, then Collections to location the collection for the Admin Tool. The default is QuickSessionCollection.
Under RemoteApp Programmes, right-click on Admin Tool, then click Edit Properties.
Click User Assignment, then select either:
All users and groups that have access to the collection.
Only specific users and groups.
If you select specific users, click Add and select the user.