[CentOS] Cannot start sm-client on CentOS

Starting up sendmail I get:

Starting sm-client: can not chdir(/var/spool/clientmqueue/): Permission denied Program mode requires special privileges, e.g., root or TrustedUser.

I assume the user used for sm-client is smmsp. However, that user has /var/spool/mqueue as homedir and I added him to the trusted users list. FYI, that user has disabled login (which should be okay) and the group has a pre-encrypted password by default. On Suse the client queue runner is run by user mail:mail which also has login disabled but no password for the group.

What do I need to change, so that sm-client runs okay on CentOS?

Kai