More clarity about storage account issue in classic metrics

Author: vgorbenko

articles/azure-monitor/platform/metrics-troubleshoot.md

@@ -92,19 +92,21 @@ In many cases, the perceived drop in the metric values is a misunderstanding of
 
 ## Cannot pick Guest OS namespace and metrics
 
-Virtual machines and virtual machine scale sets have two categories of metrics: **Virtual Machine Host** metrics that are collected by the Azure hosting environment, and **Guest OS** metrics that are collected by the [monitoring agent](agents-overview.md) running on your virtual machines. You install the monitoring agent by enabling [Azure Diagnostic Extension](diagnostics-extension-overview.md).
+Virtual machines and virtual machine scale sets have two categories of metrics: **Virtual Machine Host** metrics that are collected by the Azure hosting environment, and **Guest OS (classic)** metrics that are collected by the [monitoring agent](agents-overview.md) running on your virtual machines. You install the monitoring agent by enabling [Azure Diagnostic Extension](diagnostics-extension-overview.md).
 
 By default, Guest OS metrics are stored in Azure Storage account, which you pick from the **Diagnostic settings** tab of your resource. If Guest OS metrics aren't collected or metrics explorer cannot access them, you will only see the **Virtual Machine Host** metric namespace:
 
 ![metric image](./media/metrics-troubleshoot/cannot-pick-guest-os-namespace.png)
 
-**Solution:** If you don't see **Guest OS** namespace and metrics in metrics explorer:
+**Solution:** If you don't see **Guest OS (classic)** namespace and metrics in metrics explorer:
 
 1. Confirm that [Azure Diagnostic Extension](diagnostics-extension-overview.md) is enabled and configured to collect metrics.
     > [!WARNING]
     > You cannot use [Log Analytics agent](agents-overview.md#log-analytics-agent) (also referred to as the Microsoft Monitoring Agent, or "MMA") to send **Guest OS** into a storage account.
 
-1. Verify that storage account isn't protected by the firewall.
+1. Ensure that **Microsoft.Insights** resource provider is [registered for your subscription](metrics-troubleshoot#microsoftinsights-resource-provider-isnt-registered-for-your-subscription).
+
+1. Verify that storage account isn't protected by the firewall. Azure portal needs access to storage account in order to retrieve metrics data and plot the charts.
 
 1. Use the [Azure storage explorer](https://azure.microsoft.com/features/storage-explorer/) to validate that metrics are flowing into the storage account. If metrics aren't collected, follow the [Azure Diagnostics Extension troubleshooting guide](diagnostics-extension-troubleshooting.md#metric-data-doesnt-appear-in-the-azure-portal).