Send Email Smart Service unable to send emails

After applying hotfix for 19.1 on-premise setup send e-mail smart service is unable to send emails out. There are no logs in tomcat or mail-listener. Appian is configured to send email out, Custom.properties has all SMTP settings,  custom-email configuration.xml has the required email configurations as well appian alerts, password resets, task assigned notifications have no issues and are being sent. Any other log file i should be looking into for processuuid, custom sender emails errors?

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