Open Source Document Management System | OpenKM

A workflow has been in production for 2 months now without any glitches. This particular workflow does not include any calls to email or notifications.
All of a sudden, upon starting this workflow an error message pops op in OpenKM stating that it cannot send an email... I have reset the OpenKM server, reloaded the workflow definition but same error appears. What is my next step?

Difficult to guess with so little info.

Nothing changed to the workflow definition. Nothing changed to the OpenKM install or config. It was working fine for months... There is no way to debug this either. That's why I made the post. What info would you need?

The workflow (source and par archive), for example. Which OpenKM version are you using?