I was recently troubleshooting an Azure VPN problem for a customer, the problem was that a S2S VPN that was working correctly for months was not forming with a Cisco ASA 5505 Firewall.
The following commands can be used to reset an Azure Gateway. A Gateway is basically two instance (RRAS running in Active/Passive I believe) that are managed by Microsoft. If you run this command Azure will fail over the Active not and reboot it. The Passive node will take over.
$gateway = Get-AzureRmVirtualNetworkGateway -Name “cloud_gw” -ResourceGroup “rname”
Reset-AzureRmVirtualNetworkGateway -VirtualNetworkGateway $gateway