Update tutorial-windows-vm-access-sql.md

Error handling

Author: verargulla

articles/active-directory/managed-identities-azure-resources/tutorial-windows-vm-access-sql.md

@@ -91,6 +91,9 @@ SQL DB requires unique Azure AD display names. With this, the Azure AD accounts
     > [!NOTE]
     > `VMName` in the following command is the name of the VM that you enabled system assigned identity on in the prerequisites section.
 
+    > [!NOTE]
+    > If you encounter the following error "Principal `VMName` has a duplicate display name", append the CREATE USER statement with WITH OBJECT_ID='xxx'.
+
     ```sql
     ALTER ROLE db_datareader ADD MEMBER [VMName]
     ```