OFI not sending alerts when the rule is violdated


I have installed and configured Optimize for Infrastructure 9.6 in QA environment.
During testing, I found that it is not throwing an alert email when the rule violation happens.

I have configured the user with valid email and added in the rule. I am able to successfully send the test mail as well from OFI configuration tab. but in real time, when there is a rule violation, it doesn’t send alert emails.

Am I missing any other configuration?