When i send a email with the attachments to the external and internal members it goes fine. After that when i resend the same message with some modifications getting undeliverable message stating "The recipient could not be processed because it would violate existing security policies #MSEXCH:MSExchangeIS:/DC=com/DC=mydomain:SERVERNAME[578:0x000004DC:0x0000001D] #SMTP"
Any one can suggest me what does it meant?