No error message is seen. The Exchange Online collector is simply missing from the Archive Collector section.
The Exchange Online collector is only available when account provisioning has been set to Microsoft Office 365.
1. Navigate to Configuration | User Management in Veritas Alta Archiving Administration console.
2. Change provisioning to Manage account provisioning remotely and select the check box Using Microsoft Office 365.
3. Click on Save.
4. Navigate to Archive Collectors. The Exchange Online collector should be now available for configuration.