Hello William, and sorry for the inconvenience on this. We did recently identify some underlying issues involving the Plesk API calls to SmarterMail, and these issues will be resolved with our next public release. If you'd like a custom build including those fixes before that release please submit a ticket with us and we'd be happy to get you going in the right direction.
Kyle Kerst
IT Coordinator
SmarterTools Inc.
www.smartertools.com