Occasionally an Azure VPN connection will disconnect and not automatically reconnect again. This could be if the remote device (router or firewall on-premise) loses Internet connectivity or power. To reset the site-to-site VPN connection follow the below steps.
1. Log in to the portal for the customer affected (https://portal.azure.com)
2. Go to the “Virtual network gateways” blade down the left hand side
3. Select the Virtual Network Gateway affected and click Reset, shown in Yellow highlight below
4. You will get a notification to show that the Virtual Network Gateway is being reset
5. You should then get one to show that the Reset was successful, and connectivity should be restored.
