Work Add-Ons are licensed by user tiers, and look only for Enabled users who have Read-Write access rights. To determine how many active users there are on CRM, do an Advanced Find search of the following query:
If one's user tier has been exceeded on the addon license, limit the number of users in Dynamics 365 through Office 365 security groups.
- Prerequisite: must have global administrator rights in the Office 365 Portal- https://portal.office.com
In the Admin Application:
- On the home page, Groups
- Click on Add a Group
- Select the Type as Security Group
- And add Members to this Group.
- Navigate to Admin Centers->Dynamics 365
- Identify the Dynamics CRM instance you want to work with and Click edit
- Select the Security Group in the Security Settings.
This will now enable only the users in the Security group to have access to the Dynamics 365 instance.