@Prasannajit: Are you using the Active-Active AutoVPN feature for site-to-site with one or more other MXs? If you have Active-Active AutoVPN, I believe you will get a VPN alert when WAN 2 drops, noting that a tunnel has failed. The alert will not specify whether it's due to WAN1 or WAN2 drop, but you do get an Alert that you would likely want to investigate. Not exactly the feature for which you are looking, but might be helpful.
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