After obtaining additional information from the vendor, it's confirmed the issue was caused by vendor-controlled modifications to their software, specifically an newly implemented cleanup task meant to remove old/unused software packages from the vendor controlled environment. The vendor did not fully test this process against all deployments, and as such inadvertently removed a critical portion of the system needed to run the vendors control panel, which resulted in the spam filtering control panel being unavailable. The vendor identified the issue, disabled the faulty cleanup process, and restored service within roughly 15 hours by reinstalling the affected components. They've since put additional testing and verification steps in place to prevent this from happening again.
