You must add those users who will use the Leave Calendar within your organization. The users must be registered SharePoint users and have sufficient privileges in the Leave Calendar site. You manage the Leave Calendar from your SharePoint Administration Control Panel.
Do like this:
1. Open the SharePoint Administration panel.
2. Click apps and then Manage Licenses.
3. Click Frånvarokalender.
4. Click assign licenses
5. In the name box, type the username you want to assign a license to and click Add User.