mSmtpclient.Send (oMail) System.IndexOutOfRangeException: Index was outside the bou

Hi All,

I'm looking into an issue while sending emails through SMTP with Attachments over `3MB. The application combines multiple tif images into one pdf and the pdf is being attached to the email. We are getting the following error message.

System.Net.Mail.SmtpException: Failure sending mail. ---> System.IndexOutOfRangeException: Index was outside the bounds of the array.
at System.Net.Base64Stream.EncodeBytes(Byte[] buffer, Int32 offset, Int32 count, Boolean dontDeferFinalBytes, Boolean shouldAppendSpaceToCRLF)
at System.Net.Base64Stream.Write(Byte[] buffer, Int32 offset, Int32 count)
at System.Net.Mime.MimePart.Send(BaseWriter writer)
at System.Net.Mime.MimeMultiPart.Send(BaseWriter writer)
at System.Net.Mail.Message.Send(BaseWriter writer, Boolean sendEnvelope)
at System.Net.Mail.SmtpClient.Send(MailMessage message)

From my research I found out that there was an issue with Framework 4.0 while sending documents over 3MB but the problem is that I can't recreate the issue on my machine or QA server under 3.5 or 4.0 framework.

Any help would be greatly appreciated.

Thanks,
Bogie