Help in how to fix error code: 15

I have been trying to enable directory synchronization, but I encountered an error in the Microsoft Online Services Directory Synchronization Configuration Wizard.
The error says: "An error occurred. Error Code: 15. Error Description: Directory synchronization is not activated for this company.
How do I fix this one?

Error:
An error occurred. Error Code: 15. Error Description: Directory synchronization is not activated for this company.You can activate directory synchronization on the Microsoft online Services Admin Overview page. Tracking ID:
a8dc3520.31ea.4ff3.aa17.b7f76f95cf68 Server Name:
BL2GR1BBA00
