System.Net.Mail.SmtpException: Failure sending mail. ---> System.Threading.ThreadAbortException: Thread was being aborted

System.Net.Mail.SmtpException: Failure sending mail. ---> System.Threading.ThreadAbortException: Thread was being aborted

My code for sending mail is:

 public static string SendMail(string smtpFrom, string strPath, string strToMailAddress, string strSubject, string strBody, string strCCMailAddress, string strBccMailAddress)
        {
            try
            {
                SPSecurity.RunWithElevatedPrivileges(delegate()
                {
                    //my custom code
                    System.Web.Mail.MailMessage mail = new System.Web.Mail.MailMessage();

                    mail.From = smtpFrom;
                    mail.To = strToMailAddress;
                    mail.Cc = strCCMailAddress;
                    mail.Bcc = strBccMailAddress;
                    mail.Subject = strSubject;
                    mail.Body = strBody;
                    mail.BodyFormat = System.Web.Mail.MailFormat.Html;
                    System.Web.Mail.SmtpMail.SmtpServer = SPAdministrationWebApplication.Local.OutboundMailServiceInstance.Server.Address;

                    //System.Web.Mail.MailAttachment imgObj1 = new System.Web.Mail.MailAttachment("imagePath");
                    //mail.Attachments.Add(imgObj1);

                    //Add the attachment
                    if (!string.IsNullOrEmpty(strPath))
                        mail.Attachments.Add(new System.Web.Mail.MailAttachment(strPath));

                    System.Web.Mail.SmtpMail.Send(mail);

                });
            }
            catch (Exception ex)
            {
                SPDiagnosticsService diagSvc = SPDiagnosticsService.Local;
                diagSvc.WriteTrace(0, new SPDiagnosticsCategory("CnP", TraceSeverity.Unexpected, EventSeverity.Error), TraceSeverity.Unexpected, "SendMail - Writing to the ULS log:  {0}", new object[] { ex.ToString() });
                diagSvc.WriteTrace(0, new SPDiagnosticsCategory("CnP", TraceSeverity.Unexpected, EventSeverity.Error), TraceSeverity.Unexpected, "SendMail - Writing to the ULS log:  {0}", new object[] { ex.Message });
                diagSvc.WriteTrace(0, new SPDiagnosticsCategory("CnP", TraceSeverity.Unexpected, EventSeverity.Error), TraceSeverity.Unexpected, "SendMail - Writing to the ULS log:  {0}", new object[] { ex.StackTrace });
                return ex.Message;
            }
            return null;
        }