Update mx-azure-installation.md

Clarify permissions required

Author: MXClyde

content/en/docs/deployment/mx-azure/mx-azure-installation.md

@@ -17,7 +17,7 @@ Before starting the installation and implementation process, make sure that you
 
 * Obtain and configure a Microsoft Azure account. For more information, refer to the the Microsoft Azure documentation.
 * Purchase the Mendix on Azure offering in the [Azure Marketplace](https://azuremarketplace.microsoft.com/).
-* Enable co-access permissions for the offering.
+* The Azure account used to purchasing the offering **must** also be used to sign-in to Mendix on Azure portal. Otherwise the cluster will not be visible for initialization.
 
 {{< figure src="/attachments/deployment/mx-azure/coadmin-permission.png" class="no-border" >}}