Call method automatically every 1 minute in ASP.Net using Global.asax

https://ibb.co/kgc1Ht3

getting error like above 

What you are doing is wrong. Interval expect number not Thread.Sleep.

can you please help me out 

how to call method per each min need to call 1 min 

void Application_Start(object sender, EventArgs e)
{
    // Code that runs on application startup
    System.Timers.Timer timer = new System.Timers.Timer();    
    timer.Interval = (60*1000); // 1 Minute.
    timer.AutoReset = true;
    timer.Elapsed += new System.Timers.ElapsedEventHandler(SendSmsNotification);
    timer.Enabled = true;
}
 
public void SendSmsNotification(object source, System.Timers.ElapsedEventArgs e)
{
    SendSms.sendsmsto("xxxxxxxxx","xxxxxx");
}