diff --git a/CertificationAuthority/Validate-NDESConfiguration.ps1 b/CertificationAuthority/Validate-NDESConfiguration.ps1
index 73ac914..9be0f9c 100644
--- a/CertificationAuthority/Validate-NDESConfiguration.ps1
+++ b/CertificationAuthority/Validate-NDESConfiguration.ps1
@@ -63,7 +63,7 @@ Param(
 [parameter(Mandatory=$true,ParameterSetName="NormalRun")]
 [alias("ca")]
 [ValidateScript({
-    $Domain = (Get-WmiObject Win32_ComputerSystem).domain
+    $Domain = (Get-ADDomain).DNSRoot
         if ($_ -match $Domain) {
 
         $True