The Storage shows "Offline;Unable to connect to the OpenStorage device. Ensure that the network is properly configured between the device and the Backup Exec server"

SGMON Debug Log :
PVLSVR: DeviceIo: beost: Error: D:\Program Files\Symantec\Backup Exec\\libstspiDataDomain.dll:stspi_open_server STS_EPLUGIN [DDErrNo = 5075 (the user has insufficient access rights)]
PVLSVR: DeviceIo: beost: Error: libsts opensvh(): v12_open_server failed in plugin D:\Program Files\Symantec\Backup Exec\\libstspiDataDomain.dll err 2060046
The user account used to configure Data Domain OST Storage is in locked state.
1. Connect to Data Domain administration Web Console i.e. SS system manager
2. Go to Local Users from Administration section -> Access
3. Select the user that is used to configure Data Domain OST and click Enable.
4. Restart all BE services and confirm Data Domain OST Storage should be online.

Note: Contact Technical Support if the Storage remains offline as the root cause of the problem could be different.