“You only have administrative or read-only access to your organization. To configure the organization with Outlook, you must have read-write access”
The user needs a CRM Online license assigned as well. To assign a Microsoft Dynamics CRM Online license, sign into http://portal.office.com as a user with O365 administrative privileges and assign a Microsoft Dynamics CRM Online license to your user account. It may take a few minutes before the license information synchronizes from Office 365 to Microsoft Dynamics CRM Online.
For detailed steps on how to assign a license in Office 365, refer to the following article:
Assign or unassign licenses for Office 365 for business
Article ID: 2997751 - Last Review: 4 Feb 2016 - Revision: 1