After upgrading to Identity Manager 12.6.6 and above, emails from Workpoint workflow are no longer being sent.
The version Workpoint Workflow in Identity Manager 12.6.6 onwards is 3.5.2 which differs from previous Identity Manager releases.
In this Workpoint version the configuration of the monitors is not done through the GeneralMonitor.properties file, but rather by the wpQmonitor.xml in the same location (..\Identity Manager\IAM Suite\Identity Manager\tools\Workpoint\conf).
Edit wpQmonitor.xml and search for the string 'MailQ Monitor'.
Enter the relevant fields for Mail Monitoring.
If your SMTP server does not require a username and password in order to login, then these fields need to be removed.
Make sure to set the auto-start and notify to 'true'.
For additional details please refer to the CA Identity Manager bookshelf and the Workpoint documentation located in the Identity Manager tools folder.