Not sure what is the requirement here, CIMC do support SMTP config :
That is an "open" enhancement request, which a few other customers have asked about from time to time. By 'open' I mean unimplemented. Some enhancement requests get implemented, some do not. Just depends on the business justification (i.e. do enough customers actually request this, etc, etc)
Suggest you open a TAC case requesting information about SMTP authentication and request your case be associated with the enhancement request. This is best way to give visibility to those type of requests, in addition to talking with your Cisco Account team to relay the feature request as well.