When the Director of HR and VP of Legal send a meeting request to you.
Got the meeting request while I was out of the office - got in to find my account locked out...
Not good I think - but I was on 6 months notice so WTF...
Turns out I was being notified of a restructuring and a new boss and my account being locked out was an unfortunate coincidence.
Mind you the entire office did get the bullet about a year later - I'd left by that point as it was clear that something was up....