Now that Single Sign-On is enabled, you need to ensure that User Assignment is required within Azure Active Directory.
If you do not do this, anyone in your organisation will be able to access Radar Reporting.
Firstly, log in to the Azure Management portal as an Administrator.
Choose the directory you are using for Office 365 and click the Enterprise Applications link in the left navigation menu.
Click All Applications and then select the Office 365 Reports one.
Navigate to Properties, change the User Assignment Required to Yes and click the Save button at the top of the screen.
Single Sign-On is now enabled for your account. You will now have to grant users access to Radar Reporting inside Azure Active Directory.