cmd-let for listing all domain controller in DA entry point

I have two DA server in ELB mode. recently i got the error on dashboard for domain controller not reachable because of that all DA clients failed to have DA session for 10 mins. however the DC were pingable. I want to list all domain controllers in DirectAccess Policy-ClientToInfra endpoint list. Is there any cmd-let to list all DC's.

I have tried to use Get-DAEntryPoint and Get-DAEntryPointDC commands but its showing below error

PS C:\Windows\system32> Get-DAEntryPointDC
Get-DAEntryPointDC : You must enable a multisite deployment before performing this operation. Use the
Enable-DAMultiSite cmdlet to do this.
At line:1 char:1
+ Get-DAEntryPointDC
+ ~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (ComputerName:root/Microsoft/..._DAEntryPointDC) [Get-DAEntryPointDC], Cim
   Exception
    + FullyQualifiedErrorId : REMOTEACCESS 132,Get-DAEntryPointDC