After changing CEM to use CSSMTP instead of SMTP emails are no longer being received via CEM's Alert processing. The necessary PTF (SO09250) is applied to CEM's runtime, and the CSSMTP environment has been correctly defined in CEM (with correct values for the Domain, Writer Name (EXTWRTNAME), and Job Class).
The CEMALERT task needed to be refreshed
Release : 6.0
Component : CA COMPLIANCE EVENT MANAGER
Bouncing the CEMALERT task to pick up the new CSSMTP definitions proved successful.