Adding troubleshooting notes

Author: whhender

articles/purview/how-to-monitor-scan-runs.md

@@ -31,6 +31,13 @@ In Microsoft Purview, you can register and scan various types of data sources, a
 
 1. You can come back to **Scan Status** page by following the bread crumbs on the top left corner of the run history page.
 
+## Scans no longer run
+
+If your Microsoft Purview scan used to successfuly run, but are now failing, check these things:
+1. Have credentials to your resource changed or been rotated? If so, you'll need to update your scan to have the correct credentials.
+1. Is an [Azure Policy](../governance/policy/overview.md) preventing **updates to Storage accounts**? If so follow the [Microsoft Purview exception tag guide](create-azure-purview-portal-faq.md) to create an exception for Microsoft Purview accounts.
+1. Are you using a self-hosted integration runtime? Check that it's up to date with the latest software and that it's connected to your network.
+
 ## Next steps
 
 * [Microsoft Purview supported data sources and file types](azure-purview-connector-overview.md)