Ciao ragazzi, se cerco di inviare una mail in locale funzione in web mi dà questo errore sapete perchè?

Server Error in '/' Application.
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The transport failed to connect to the server.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Runtime.InteropServices.COMException: The transport failed to connect to the server.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:


[COMException (0x80040213): The transport failed to connect to the server.
]

[TargetInvocationException: Exception has been thrown by the target of an invocation.]
System.RuntimeType.InvokeDispMethod(String name, BindingFlags invokeAttr, Object target, Object[] args, Boolean[] byrefModifiers, Int32 culture, String[] namedParameters) +0
System.RuntimeType.InvokeMember(String name, BindingFlags invokeAttr, Binder binder, Object target, Object[] args, ParameterModifier[] modifiers, CultureInfo culture, String[] namedParameters) +473
System.Web.Mail.LateBoundAccessHelper.CallMethod(Object obj, String methodName, Object[] args) +58

[HttpException (0x80004005): Could not access 'CDO.Message' object.]
System.Web.Mail.LateBoundAccessHelper.CallMethod(Object obj, String methodName, Object[] args) +111
System.Web.Mail.CdoSysHelper.Send(MailMessage message) +1859
System.Web.Mail.SmtpMail.Send(MailMessage message) +150
PuntosanzioniWEB.registrazione.Button1_Click(Object sender, EventArgs e) in C:\Inetpub\wwwroot\PuntosanzioniWEB\registrazione.aspx.vb:66
System.Web.UI.WebControls.Button.OnClick(EventArgs e) +108
System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +57
System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +18
System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +33
System.Web.UI.Page.ProcessRequestMain() +1292




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Version Information: Microsoft .NET Framework Version:1.1.4322.2300; ASP.NET Version:1.1.4322.2300