As you may have already experienced, troubleshooting network connectivity issues (either with Azure VNets or in hybrid configuration with VPN/Express Route back to on-premises) can be quite challenging.
While Microsoft has been providing network troubleshooting capabilities (with Network Watcher), it is still a time consuming and difficult.
Well, good news, you can now use Azure Monitor to help you investigating network issues – even at some point becoming proactive.
To start using Azure Monitor to help troubleshooting network connectivity issues, logon to your Azure portal (https://portal.azure.com/) and reach out to your Azure Monitor
Then go to the Insights\Networks blade
There you will have all network related (network security groups, virtual networks…) listed with their status (available/healthy, degraded or unavailable/unhealthy) with a summary of network related alerts
Then for each of network resource categories (security group, virtual network) you can have the complete list of all related resources and their specific state and alert