Looks like Cyren has given the all-clear on their Service Status page:
"Update - as of 16:05 UTC the Anti-Spam service in all Data Centers is fully operational."
If you disabled the Cyren spam check while the issue was occurring, you can now re-enable it within SmarterMail.
Andrea Free
SmarterTools Inc.
877-357-6278
www.smartertools.com