Below is an error that you can get in PowerShell or via STSADM for SharePoint
PS C:\> Get-SPServiceApplicationProxy
Get-SPServiceApplicationProxy : The farm is unavailable.
At line:1 char:30
+ Get-SPServiceApplicationProxy <<<<
+ CategoryInfo : ResourceUnavailable: (Microsoft.Share...pplicationProxy:SPCmdletGetServiceApplicationProxy) [Get-SPServiceApplicationProxy], InvalidOperationException
+ FullyQualifiedErrorId : Microsoft.SharePoint.PowerShell.SPCmdletGetServiceApplicationProxy