24 hours timer not working

Hi....

i am using a timer to invoke method and send daily mails. but its not working the timer which i had given is.I kept it in Global.asax page

myTimer.Interval = 86400000;
&
myTimer.Interval =1000*60*60*24;

i tried these two. if i kept it for 15 min it is working fine.


Thanks in advance....