The below error can be seen when attempting to access Folder Sync Online configuration in Alta Archiving Administration Console under Archive Collectors | Exchange Online | Folder Sync Configuration despite having Exchange Online Folder Sync service enabled.
The customer has not purchased Exchange online folder sync service.

This happens when the Partner Company associated with the customer, does not have the Exchange Online Folder Sync service enabled.
Raise a support case with Veritas Support, so that this can be resolved.