Error 414 Z axis error detect- servo alarm

I'm using a Hwacheon Ecomil 65V with Fanuc 18M controller and have been getting an error on startup "Error 414 Z axis error detect- servo alarm." The last time this error came up, the oil reservoir required filling and after doing so, the machine worked fine. The error came up again recently. The reservoir was filled and the machine worked fine for the day. The next day when trying to start the machine, the error returned. The oil levels are still fine. What I noticed was that on startup when the error shows up, the oil cooling unit does not turn on and there is no oil circulation visible in the sightglass above the spindle. I understand that this error MAY be due to poor lubrication of the ways but I can't move any axis of the machine to get anything going. Any ideas? Thanks a lot,

Andrew