Microsoft .NET SP1 has the default timeout value for the XML Web service calls set to 100000 ms. If you use this default value, some of your calls will never have a chance to complete. We've experienced the following error message related to this problem:
An unhandled exception of type 'System.Net.WebException' occurred in system.Web.services.dll Additional information: The operation has timed-out.
You may receive a different message but the cause may still be the same -- the default timeout value is too low. To avoid this problem, set the appropriate timeout value or set the timeout value to infinite, as shown in the following example:
MyService service1 = new MyService();
// Infinite timeout.
service1.Timeout = -1;
// The timeout is set to 10 minutes.
service1.Timeout = 10 * 60 * 1000;