This can be caused by serveral issues, all related to your RBS Server's license. Some of these reasons can only be resolved by contacting RBS technical support 9-5 US Central Time weekdays except holidays. If you need to resolve this issue during off hours, you can use Emergency Help After Hours at this link: http://www.remote-backup.com/support/
You might also try running the automatic Repair Wizard or the procedure at this link:
1. The RBS Server software has been migrated to a different computer or VM without following the correct procedure as outlined at the following link. Try uninstalling the first instance of the RBS Server using Add/Remove Programs. This will reset your available license count.
RBS Server Migration: http://help.remote-backup.com/index.php?/Knowledgebase/Article/View/252/0/how-to-movemigrate-the-rbs-server-and-clients-data-to-another-drive-or-computer---official-procedure
If you have recently moved your RBS Server to another computer or VM, and it will not start, please go to the following link and move your RBS Server license. [move server license here]
2. The RBS Server software is installed on more than the authorized number of computers. Uninstall one of them using Add/Remove Programs. This will reset your available license count.
3. Your serial number has been compromised and used by someone else illegally. Never disclose your serial number. Contact RBS Tech Support.
4. Port 80 is blocked from your RBS Server to the RBS authentication server at remote-backup.com. Unblock port 80.
5. You have attempted to upgrade your RBS Server software with an unauthorized download. This happens most often if you obtain an upgrade package from someplace other than the official download location on the remote-backup.com website. Re-download using your authorized serial number for the RBS Server you want to upgrade.
6. You have attempted to upgrade your RBS Server software using an unauthorized download while your Maintenance Subscription has lapsed. (see above). Contact RBS Tech Support.
7. You have multiple serial numbers and you have applied an upgrade to an RBS Server using an upgrade package downloaded for a different serial number. Re-download the upgrade package using the serial number for the RBS Server you want to upgrade.