                 $set:
                     status: STATUS_NOTCOMPLETE
                     'data.maxTimestampMs': maxTimestamp
-            , ->
+            , (err) ->
 
                 # insert into queue again
                 Chat.request taskId

                    minLngE6:        Math.round(Config.Region.SouthWest.Lng * 1e6)
                    maxLatE6:        Math.round(Config.Region.NorthEast.Lat * 1e6)
                    maxLngE6:        Math.round(Config.Region.NorthEast.Lng * 1e6)
                    minTimestampMs:  TSmin
                    maxTimestampMs:  TSmax
                    chatTab:         type
                status: STATUS_PENDING
                _id:    new ObjectID()

        if response.length < Config.Chat.FetchItemCount

            # no more messages: remove task
            delete Chat.tasks[taskId]
            Chat.length--

