Nethvoice voicemails recognized as spam due to invalid header #7461
Description
The problem appears to be caused by the presence of two Content-Type headers in the email message.
Upon examining the email headers, the rule MULTIPLE_UNIQUE_HEADERS was triggered due to the presence of duplicate Content-Type headers:
Content-Type: multipart/mixed; boundary="----voicemail_1350712061221135"
Content-Type: text/plain; charset=utf-8
According to email standards (RFC 2045 and RFC 5322), an email should have only one valid Content-Type header for the entire message.
Since Content-Type, as Date header, is automatically added by s-nail