I think the reason is a wrong owner for the file 'access.db'. Also check owner for 'aliases.db'.
Correct is the user root. Try:
chown root:smmsp /etc/mail/access.dbIf it doesn't work, check owner for the other files and directorys.
A complete decription you can find in "sendmail 8.13 Compandium" from Brian Costales, Chapter 10, Maintain security with sendmail. Or try this link:
https://blue-labs.org/software/sm-pgsql/
Regard
s, Tobias