system.net.mail 发送邮件问题（急在线等！）
在公司测试没问题，拿到客户那里出现以下异常：

System.Net.Mail.SmtpException: Failure sending mail. ---> System.FormatException: Invalid length for a Base-64 char array.
at System.Convert.FromBase64String(String s)
at System.Net.NTAuthentication.GetOutgoingBlob(String incomingBlob)
at System.Net.Mail.SmtpNtlmAuthenticationModule.Authenticate(String challenge, NetworkCredential credential, Object sessionCookie)
at System.Net.Mail.SmtpConnection.GetConnection(String host, Int32 port)
at System.Net.Mail.SmtpTransport.GetConnection(String host, Int32 port)
at System.Net.Mail.SmtpClient.GetConnection()
at System.Net.Mail.SmtpClient.Send(MailMessage message)
--- End of inner exception stack trace ---
at System.Net.Mail.SmtpClient.Send(MailMessage message)
at _Default.sendmail() in c:\WebSite2\Default.aspx.cs:line 90 ');

问题解决马上结帐！！

[解决办法]

问题解决``是SMTP验证问题`