C# System.Security.Cryptography.CryptographyException:句柄无效

我通过C#for发送邮件时遇到异常

asSystem.Security.Cryptography.CryptographyException:句柄无效。

MailMessage mail = new MailMessage(from,to);

            mail.To.Add(to);
            mail.From = new MailAddress(from, "", System.Text.Encoding.UTF8);

            mail.Subject = "This is a test mail";

            mail.SubjectEncoding = System.Text.Encoding.UTF8;

            mail.Body = fr.message;

            mail.BodyEncoding = System.Text.Encoding.UTF8;

            mail.IsBodyHtml = true;

            mail.Priority = MailPriority.High;

            SmtpClient client = new SmtpClient();

            //Add the Creddentials- use your own email id and password
            client.Credentials = new System.Net.NetworkCredential(from, Password);

            client.Port = 587; // Gmail works on this port

            client.Host = "smtp.gmail.com";

            client.EnableSsl = true; //Gmail works on Server Secured Layer

                client.Send(mail);

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我不明白为什么会发生这种情况？

请检查项目设置，并确保已检查NTLM身份验证：

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ssl的端口不是

465

的可能重复项吗？这不是重复项。另一个问题在

MailMessage

构造函数上有一个例外，但在这里它发生在

SmtpClient

构造函数上。另外，另一个问题没有真正的答案。请尝试将您的邮件和SmtpClient包装在

使用
块中：
使用（var mail=new MailMessage（…）{…使用（var client=new SmtpClient（…）{…}
我在另一个威胁中找到了解决方案。请查收
MailMessage mail = new MailMessage(from,to);

            mail.To.Add(to);
            mail.From = new MailAddress(from, "", System.Text.Encoding.UTF8);

            mail.Subject = "This is a test mail";

            mail.SubjectEncoding = System.Text.Encoding.UTF8;

            mail.Body = fr.message;

            mail.BodyEncoding = System.Text.Encoding.UTF8;

            mail.IsBodyHtml = true;

            mail.Priority = MailPriority.High;

            SmtpClient client = new SmtpClient();

            //Add the Creddentials- use your own email id and password
            client.Credentials = new System.Net.NetworkCredential(from, Password);

            client.Port = 587; // Gmail works on this port

            client.Host = "smtp.gmail.com";

            client.EnableSsl = true; //Gmail works on Server Secured Layer

                client.Send(mail);