Update agent-windows.md

Product Backlog Item 13790528: Upgrade doc to make it clear WinGA's automatic update needs access to Azure Storage

Author: axelgMS

articles/virtual-machines/extensions/agent-windows.md

@@ -122,7 +122,7 @@ When logged in to a Windows VM, Task Manager can be used to examine running proc
 
 
 ## Upgrade the VM Agent
-The Azure VM Agent for Windows is automatically upgraded on images deployed from the Azure Marketplace. As new VMs are deployed to Azure, they receive the latest VM agent at VM provision time. If you have installed the agent manually or are deploying custom VM images you will need to manually update to include the new VM agent at image creation time.
+The Azure VM Agent for Windows is automatically upgraded on images deployed from the Azure Marketplace. The new versions are stored in Azure Storage, so please ensure you don't have firewalls blocking access. As new VMs are deployed to Azure, they receive the latest VM agent at VM provision time. If you have installed the agent manually or are deploying custom VM images you will need to manually update to include the new VM agent at image creation time.
 
 ## Windows Guest Agent Automatic Logs Collection
 Windows Guest Agent has a feature to automatically collect some logs. This feature is controller by the CollectGuestLogs.exe process.