General Suggestions Across All Accounts:
SPF_HELO_NONE
Action: Ensure that your HELO domain publishes a valid SPF record. While this rule currently has no scoring impact, it’s best to fix it as it might in future updates. This helps email servers verify the origin of the email.
DKIM_INVALID
Action: Your DKIM signature exists but is invalid, significantly impacting your score. Check your DKIM setup to ensure the signature is correctly generated and valid for the domain. This often involves fixing DNS records and ensuring DKIM signing works correctly on the email server.
DMARC_NONE / DMARC_MISSING
Action: Set up a DMARC policy for your domain. DMARC helps ISPs determine how to handle emails that fail SPF or DKIM checks. Without it, emails may appear less secure, resulting in a higher chance of landing in spam.
MSGID_MULTIPLE_AT
Action: Your Message ID contains something unacceptable according to RFC standards. Review the configuration of the email server or tool generating your email headers to correct the message ID format.
INVALID_MSGID
Action: Ensure the Message ID complies with RFC 2822. Fix any formatting issues in the Message ID header, as invalid Message IDs may raise suspicion.
FREEMAIL Issues (e.g., FREEMAIL_REPLYTO_END_DIGIT, FREEMAIL_FROM)
Action: If possible, avoid using free email providers (e.g., Gmail, Yahoo) for sending cold emails. Use a domain-specific email address to appear more professional and reduce the risk of being flagged as spam.
RDNS_NONE (1.30)
Action: Set up reverse DNS (rDNS) for the IP addresses sending your emails. rDNS must be resolved in your domain, as lacking rDNS can raise suspicion with spam filters.
MIME_HTML_ONLY / HTML_MIME_NO_HTML_TAG
Action: Ensure your HTML emails include proper structure and at least some plain text content. A lack of plain text versions and missing key HTML tags (like
<html>) may flag your email as suspicious.
URIBL_BLOCKED / URIBL_DBL_BLOCKED / URIBL_ABUSE_SURBL
Action: URIBL indicates that URLs in your emails might be listed on a blocklist. Check your URLs against blocklists such as SURBL, and ensure they are clean. Avoid using blacklisted domains in your email links.
ARC and DKIM Settings
Action:
ARC_SIGNED / ARC_VALID: These indicate that the email has an ARC (Authenticated Received Chain) signature. Since these are functioning correctly, continue maintaining the ARC signature if your email service supports it.
DKIM_SIGNED / DKIM_VALID: Keep DKIM signatures valid. While you have DKIM signatures, it can be flagged it as invalid. Verify the keys and ensure proper signing.
Others: AXB_X_FF_SEZ_S (1.00): This indicates that a spam filter (likely Microsoft Forefront) flagged your email as spam. You may need to ensure proper authentication and review email content for spammy elements.
Read out our detailed blog on SpamAssassin. Read it here!
Additional Best Practices:
Improve Your List Hygiene:
Ensure your email list is clean and verified. Remove hard bounces, and avoid sending to spam traps.
Use email validation services to ensure that the contacts are valid and active.
Avoid Spammy Keywords and Phrasing:
Review the content of your email for spammy language or suspicious phrases that could trigger filters.
Lower Your HTML-to-Text Ratio:
Sending emails that are entirely HTML without a plain-text version can trigger spam filters. Include both a plain-text version and an HTML version in your email.
By addressing the above issues, you can significantly reduce your SpamAssassin score and improve your chances of reaching the inbox.