“554 5.5.2 Invalid data in message> #SMTP#” non delivery report in E2K7

If you get a “554 5.5.2 Invalid data in message> #SMTP#” non delivery report while sending emails with attachments between different domains (E2K7\E2K3)

Check your Firewall, some have a header size restriction that blocks messages from being sent or where Content-Type has a maximum field of 200 bytes.

E-mails that exceed this restriction will be denied with the error you are receiving. E2k7 adds additional fields to the header (i.e. date information, header length) that E2k3 doesn't add.

The solution is to change the settings of the firewall by adding these entries bellow to change the length of the headers allowed:

smtpd.length.Content-Type

and

smtpd.length.Content-Disposition