After the email server for an on-premise controller is enabled, AppDynamics recommends changing the admin user email from the default email for heightened security.
Troubleshoot Notifications
If you do not receive notifications for health rule violations, it could be because the default SMTP server timeout period is too short. To troubleshoot, increase the value of the mail.smtp.socketiotimeout Controller Setting in theAdministration Console. The default value is 30 seconds.