Getting error message while trying to mount a disk using restore agent

Hi,
I've been using the restore agent to try and mount a disk but I keep on getting an error. If you need any more information let me know, please see error message in picture below
Thanks

Failed to mount disk (Disk Id <6000C298-bb3c-ObFl-2eb3-3269d56450a6>) in Backup <da148976-1 lOa-4567-bc38-15F28d37ba26>. Server Error: <Failed to reconfigure virtual machine, Error from vCenter Server is Failed to add disk scsiO:3..>.
OK
