I created a standard "contact us" form, using the sample code on WinSite. I kept getting errors, so I tried different settings (incl port). Although I had created a mail account "[email protected]" and wanted to send the mail to that account, WinSite support suggested I authenticate using the postmaster account. Still no luck. My current code below has debug output as well. protected void btnSend_Click(object sender, EventArgs e) { try { //code from Winhost //create the mail message MailMessage mail = new MailMessage(); //set the addresses mail.From = new MailAddress(txtFrom.Text.Trim()); mail.To.Add("[email protected]"); mail.To.Add(txtFrom.Text.Trim()); //set the content mail.Subject = "SupportRequest/Comment: " + txtSubject.Text.Trim(); mail.Body = txtMessage.Value.Trim(); NetworkCredential Credentials = new NetworkCredential(); Credentials.Domain = "ComputerWhizard.com"; lblStatus.Text = lblStatus.Text + " set network credentials domain: " + Credentials.Domain.ToString(); Credentials.UserName = "[email protected]"; lblStatus.Text = lblStatus.Text + " setting network credentials username=" + Credentials.UserName.ToString(); Credentials.Password = "********"; //rem out password lblStatus.Text = lblStatus.Text + " setting network credentials username=" + Credentials.Password.ToString(); SmtpClient smtp = new SmtpClient("mail.computerwhizard.com"); smtp.Credentials = Credentials; smtp.Host = "mail.computerwhizard.com"; lblStatus.Text = lblStatus.Text + " smpt.host=" + smtp.Host.ToString(); //smtp.Port = 587; //lblStatus.Text = lblStatus.Text + " smpt.Port=" + smtp.Port.ToString(); lblStatus.Text = lblStatus.Text + " sending mail"; smtp.Send(mail); //smtp.Send(txtFrom.Text.Trim(), "[email protected]; " + txtFrom.Text.Trim(), "SupportRequest/Comment: " + txtSubject.Text.Trim(), txtMessage.Value.Trim()); lblStatus.Text = lblStatus.Text + " Mail Sent"; } catch (Exception ex) { lblStatus.Text = ex.ToString(); } } The exception is: System.Security.SecurityException: Request for the permission of type 'System.Security.Permissions.EnvironmentPermission, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed. at System.Security.CodeAccessSecurityEngine.Check(Object demand, StackCrawlMark& stackMark, Boolean isPermSet) at System.Security.CodeAccessSecurityEngine.Check(CodeAccessPermission cap, StackCrawlMark& stackMark) at System.Security.CodeAccessPermission.Demand() at System.Net.NetworkCredential.get_Domain() at CWAspNetWebApp.About.btnSend_Click(Object sender, EventArgs e) in C:\Users\Brad\Documents\My Web Sites\CWAspNetWebApp\CWAspNetWebApp\About.aspx.cs:line 36 The action that failed was: Demand The type of the first permission that failed was: System.Security.Permissions.EnvironmentPermission The Zone of the assembly that failed was: MyComputer I saw some posts with Mail issues from ASP.net, but not this error. Any suggestions?
