Add a note about separate accounts

Author: davidbel

articles/virtual-desktop/authentication.md

@@ -5,7 +5,7 @@ services: virtual-desktop
 author: Heidilohr
 ms.service: virtual-desktop
 ms.topic: conceptual
-ms.date: 09/22/2022
+ms.date: 02/21/2023
 ms.author: helohr
 manager: femila
 ---
@@ -17,6 +17,9 @@ In this article, we'll give you a brief overview of what kinds of identities and
 
 Azure Virtual Desktop supports different types of identities depending on which configuration you choose. This section explains which identities you can use for each configuration.
 
+>[!IMPORTANT]
+>Azure Virtual Desktop doesn't support signing in to Azure AD with one user account and signing in to Windows with a separate user account.
+
 ### On-premises identity
 
 Since users must be discoverable through Azure Active Directory (Azure AD) to access the Azure Virtual Desktop, user identities that exist only in Active Directory Domain Services (AD DS) aren't supported. This includes standalone Active Directory deployments with Active Directory Federation Services (AD FS).