The TrendMicro OfficeScan Server maintainance window occurs every Tuesday night from 9PM to 1AM. During this time there is a possiblity that the OfficeScan servers (TABVMTREND1-TABVMTREND3) may be temporarily brought offline for scheduled updates or routine maintenance.
OfficeScan clients that are connected to TABVMTREND1 will be unable to connect the OfficeScan (TABVMTREND1) server during this time however clients will still continue to receive virus definitions and web reputation services directly from Trend Micro.