The most common reason for this problem is the confusion between a message's
From: header and its SMTP envelope-from value (and, in different circumstances, its
To: header and SMTP envelope-to value). While the value in the
From: header is displayed in email clients (such as Microsoft Outlook), it is the SMTP envelope-from value that PureMessage checks against entries in the Whitelisted Senders and Blacklisted Senders lists.
Because the SMTP envelope values are derived from information gathered by the servers that relay the message, they are more reliable than
To: headers, which can be easily forged by the person who sends the message. There are both legitimate reasons (such as mailing lists) and illegitimate reasons (address forgery) why the contents of the SMTP envelope-from and
From: header sometimes do not match.
What to do
To view the SMTP envelope-from of a message, select the message in the PureMessage quarantine, and then view the contents of the Envelope From field on the Quarantine Info tab. Use the message's SMTP envelope-from value to update the Whitelisted Senders or Blacklisted Senders list.