Hi Rahul,
Alert Supression, which actually supresses further alerts and increases the repeat count contradicts with the mail notifications. What I mean is that you cannot send a notification on a supressed alert.
From:
Notification of Operations Manager alerts may not be received
https://learn.microsoft.com/en-us/troubleshoot/system-center/scom/cannot-receive-alert-notification
In System Center 2012 Operations Manager, the alert notification will be sent when the alert first meets all criteria, regardless of resolution state, unless resolution state itself is a criterion. If alert suppression is enabled for the rule or monitor that raises an alert, only one notification will be sent when the subscription criteria are first met. No additional notifications will be sent until the alert is closed and a new alert is raised that meets all subscription criteria.
it comes from an article about SCOM 2012 but the logic remains the same in the newer SCOM versions.
I fear that this is something you cannot change.
(If the reply was helpful please don't forget to upvote and/or accept as answer, thank you)
Regards
Stoyan Chalakov