客户端网站中出现异常错误

我刚刚在客户的网站上创建了一个帐户（我为他创建的）。两年前，我对这个网站进行了广泛的测试，没有发现任何问题。自网站发布以来，我一直在测试它，以确保它每个月都能顺利运行。

我刚刚在他的网站上创建了一个新帐户，我收到了这个错误：

Server Error in '/' Application.
Mailbox unavailable. The server response was: <me@myemail.com> No such user here 
  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.Net.Mail.SmtpFailedRecipientException: Mailbox unavailable. The server response was: <me@myemail.com> No such user here
Source Error: 

Line 62:                         HttpUtility.UrlEncode(token));
Line 63: 
Line 64:                     WebMail.Send(
Line 65:                         email,
Line 66:                         "Please confirm your Account.",

 Source File:  d:'HostingSpaces'website'website.com.au'wwwroot'Protected'Account'Register.cshtml    Line:  64 
Stack Trace: 

[SmtpFailedRecipientException: Mailbox unavailable. The server response was: <me@myemail.com> No such user here]
   System.Net.Mail.SmtpTransport.SendMail(MailAddress sender, MailAddressCollection recipients, String deliveryNotify, SmtpFailedRecipientException& exception) +1229659
   System.Net.Mail.SmtpClient.Send(MailMessage message) +1772
   System.Web.Helpers.WebMail.Send(String to, String subject, String body, String from, String cc, IEnumerable`1 filesToAttach, Boolean isBodyHtml, IEnumerable`1 additionalHeaders, String bcc, String contentEncoding, String headerEncoding, String priority, String replyTo) +686
   ASP._Page_Protected_Account_Register_cshtml.Execute() in d:'HostingSpaces'website'website.com.au'wwwroot'Protected'Account'Register.cshtml:64
   System.Web.WebPages.WebPageBase.ExecutePageHierarchy() +208
   System.Web.WebPages.WebPage.ExecutePageHierarchy(IEnumerable`1 executors) +68
   System.Web.WebPages.WebPage.ExecutePageHierarchy() +123
   System.Web.WebPages.StartPage.RunPage() +19
   System.Web.WebPages.StartPage.ExecutePageHierarchy() +67
   System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage) +78
   System.Web.WebPages.WebPageHttpHandler.ProcessRequestInternal(HttpContextBase httpContext) +121


Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.272 

什么？？？下面列出的电子邮件地址是我用来创建帐户的电子邮件地址。在收到这个错误后，我用我所有的邮件在线登录了那个电子邮件帐户，它就在那里。所以用户确实存在。那么，为什么WebPages框架会认为这个用户在尝试向其发送电子邮件确认时不存在呢？

你在代码中看到的电子邮件变量——它的值列在异常本身中。