Exchange mail level backup has permission problems when run by the scheduler

If your Exchange mail-level backup runs successfully when run manually, but fails with permission problems when run by the scheduler, then set the Online Backup Scheduler service to run using an account with appropriate permissions to access the Exchange mailboxes. 

Steps:

1. Open Control Panel -> Administrative Tools -> Services
2. Right click on the Online Backup Scheduler service
3. Select the Log On tab
4. Select This Account
5. Enter account credentials for an account that has full access to the Exchange server.