"System.Web.Mail.SmtpMail.Send" fails with large attachments

The mail was sent with the attachments of 10286 KB (10.04 MB)

But, The mail was not sent with the attachments of 15356 KB (14.99 MB) but the attachments were attached to the application successfully and I did not receive any error.

I have done the following in my ASP.Net application

            Web.Mail.SmtpMail.SmtpServer = "10.2.3.6"            mail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpauthenticate", 1)            mail.Fields.Add("http://schemas.microsoft.c ...