Reverse DNS setting for Azure Virtual Machines

Hi,

We try to build mail servers on Azure. So, we need to set reverse DNS record to VM's static global IP address.

But I got an error by using PowerShell cmdlets.

***********************************************

PS C:¥> Login-AzureRmAccount

Environment:AzureCloud

Account:****@****

TenantId:*****

SubscriptionId:*****

SubscriptionName:*****

CurrentStorageAccount:

PS C:¥> $pip = Get-AzureRmPublicIpAddress -Name XXX.XXX.XXX.XXX -ResourceGroupName *****

Get-AzureRmPublicIpAddress : Resource group '*****' could not be found.

StatusCode: 404

ReasonPhrase: Not Found

OperationID: '*****'

Line:1 character:8

+ categoruInfo:CloseError: (:) [Get-AzureRmPublicIpAddress], NetworkCloudException

+ FullyQualifiedErrorId:Microsoft.Azure.Commands.Networdk.GetAzurePublicIpAddressCommand

***********************************************
Any ideas what I could do to fix this issue?

Thanks,

Yoshihisa