Alert never ends and freezes MT5

[traderz]

What is wrong with this alert? That sound never ends and finally it freezes MT5.

        manageAlerts(time[rates_total-1],rates_total);

            return(rates_total);
           }

         //+------------------------------------------------------------------+
         void manageAlerts(datetime currTime,int bars)
           {
            if(alertsOn)
              {
               datetime time = currTime;
               int whichBar = 0; if(!alertsOnCurrent) whichBar = 1;
               static string  previousAlert1="nothing";
               static datetime previousTime1=0;
               if(Up[whichBar]!=EMPTY_VALUE) doAlert(previousTime1,previousAlert1,time,"trend changed to up");
               if(Dn[whichBar]!=EMPTY_VALUE) doAlert(previousTime1,previousAlert1,time,"trend changed to down");
              }
           }

         //+------------------------------------------------------------------+
         //|                                                                  |
         //+------------------------------------------------------------------+
         void doAlert(datetime &previousTime,string &previousAlert,datetime forTime,string doWhat)
           {
            string message;

            if(previousAlert!= doWhat || previousTime!=forTime)
              {
               previousAlert  = doWhat;
               previousTime   = forTime;
               message=TimeToString(TimeLocal(),TIME_SECONDS)+" "+_Symbol+" Brain trend signal "+doWhat;
               if(alertsMessage) Alert(message);
               if(alertsEmail) SendMail(_Symbol+" Brain trend",message);
               if(alertsSound) PlaySound("alert2.wav");
              }
           }