This looks like an old bug fixed a long time ago. Please check you're running the latest version (smeserver-dovecot-0.1.5-1.beta0) and if not, upgrade with
yum --enablerepo=fws-testing update smeserver-dovecot
Note: this packager is in our testing repo because it'd obsolete a core package. But it's stable, and used in production for several years on a lot of different servers. It stays in the testing area just to be sure it won't be installed by mistake.