Sugar Connect getting "Invalid authorization in Sugar Please, log in to your Sugar account and re-enable Sugar Connect sync."

We're trying to get our SugarCRM instance calendars synced with our MS Office 365 calendars.  Have followed all instructions online.  The sync seems to happen once and then hangs on syncing contacts (spinning wheel).  And we get a "Invalid authorization in Sugar
Please, log in to your Sugar account and re-enable Sugar Connect sync.
" error.  Support seem to be stumped on this one.  Anyone else experienced this?