SmProvider (2002) 5064

I have Dell PowerEdge R710 server (under Microsoft Windows Server 2012), connected to MD3200i disk storage.

I see in event log next error:

Source: SmProvider

Category: (2002)

ID: 5064

The controller is not available. Possible causes include network or connection problems, controller problems, or no power to the Host or storage system. If you just changed the logical unit number (LUN) mapping for an access volume, you must restart SANtricity Storage Manager Agent for the change to take effect. If you suspect a controller problem, use the Recovery Guru in SANtricity Array Management Window.

What's is the problem?