Our system moved from Windows Server 2003(Enterprise SP2) & IIS 6.
And new system is Windows Server 2012(Standard) and IIS 6(for smtp mail) & 8.
I copied all of web application files and IIS settings, another function is ok but..
email system is something wrong.
for example,
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exception: system.Net.Mail.SmtpException: cannot get iis pickup directory.

line 284: SendMail sendmail = new SendMail();
line 285: sendmail.GetSendMail(messagefrom, Useremail, mailsubject, message);

stack trace: [SmtpException: cannot get iis pickup directory.]
System.Net.Mail.IisPickupDirectory.GetPickupDirectory() +1894
System.Net.Mail.SmtpClient.Send(MailMessage message) +1956518
CommonDll.SendMail.GetSendMail(String messagefrom, String Useremail, String mailsubject, String message) +466
ASP.common_users_courserecordadd_aspx.AddBtn_Click(Object sender, EventArgs e) in d:\"sourcefile.aspx":285
System.Web.UI.WebControls.Button.OnClick(EventArgs e) +115
System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +140
System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +29
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2981

Microsoft .NET Framework v:2.0.50727.6407; ASP.NET v:2.0.50727.6387
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in Develop server(2008 R2 Ent SP1, IIS6 & 7.5), it works well.
confused.