SpamAssassin rule
MISSING_HEADERS
No To header
+1.207 points
Header test
What MISSING_HEADERS means
The message has no To header (recipients only in Bcc).
The rule's description in SpamAssassin: “Missing To: header”
How to fix it
Send each recipient an individual message with their address in To, instead of one message with everyone in Bcc.
Does your email trigger MISSING_HEADERS?
Send it to a free test address: we run SpamAssassin, check SPF, DKIM and DMARC and show every rule with a fix.
Open the email spam checkerRelated rules
FROM_EXCESS_BASE64From header needlessly encoded
INVALID_DATEInvalid Date header
MAILING_LIST_MULTILooks like mailing-list software
MISSING_DATENo Date header
MISSING_FROMNo From header
MISSING_MIDNo Message-ID header
MISSING_SUBJECTNo subject
MSGID_FROM_MTA_HEADERMessage-ID added by a relay
REPLYTO_WITHOUT_TO_CCReply-To but no To or Cc
Frequently asked questions
What does MISSING_HEADERS mean?
The message has no To header (recipients only in Bcc).
How do I fix MISSING_HEADERS?
Send each recipient an individual message with their address in To, instead of one message with everyone in Bcc.
How many points does MISSING_HEADERS add?
1.207 points in the default SpamAssassin ruleset (network tests on, Bayes off). A message is treated as spam from 5.0 points. Mail servers can change scores locally.