Why does SpamAssassin give positive score for DMARC reject and MIME_NO_TEXT or LONG_INVISIBLE_TEXT?

Email marketer from Reddit explains that SpamAssassin scoring is cumulative. Even if the individual score for DMARC_REJECT is low, if combined with other factors like missing plain text or hidden text, it can push the overall score into spam territory.

Email marketer from Email Marketing Forum suggests MIME_NO_TEXT can be triggered if the MIME structure is incorrect or incomplete. Ensure proper MIME headers and the correct encoding are used to avoid this issue.

Email marketer from Mailjet suggests avoiding techniques that hide content from users, such as using small font sizes or placing text behind images. These practices are often associated with spam and can trigger rules like LONG_INVISIBLE_TEXT in SpamAssassin.

Email marketer from StackOverflow cautions that even if hidden text is meant for SEO and not directly for spamming email recipients, it can still raise flags with spam filters like SpamAssassin if the email looks suspicious. It is recommended to avoid this practice completely.

Email marketer from Email Geeks shares experience with a web host using SpamAssassin and notes that DMARC rules are triggered if the email doesn’t pass underlying checks, such as DKIM signing, and the DMARC policy is reject. Mentions KAM_DMARC_REJECT rules, which are custom rules from The McGrail Foundation, and links to McGrail's website for more details.

Email marketer from Reddit shares that including a plain text version of your email is generally good practice for deliverability. While not always a direct cause for SpamAssassin to mark as spam, it helps ensure compatibility across different email clients and reduces the likelihood of being flagged due to incomplete MIME structure.

Email marketer from Email Geeks explains to identify the reason for invisible text being flagged in SpamAssassin, you need to check the rule regex. There are rules looking at body font sizes and colors that trigger this.

Email marketer from Litmus shares that while a DMARC reject policy itself shouldn't directly cause a high spam score, the absence of proper authentication (SPF, DKIM) combined with a reject policy can lead to increased scrutiny from spam filters like SpamAssassin.

Email marketer from Email on Acid indicates while HTML emails are visually appealing, failing to include a plain text version can raise red flags with spam filters. Ensure your emails have both versions to avoid MIME_NO_TEXT or similar rules.

Email marketer from SendPulse shares that positive scores from rules like DMARC_REJECT and MIME_NO_TEXT contribute to the overall spam score. Focusing on authentication and providing clear, accessible content (avoiding hidden text) helps reduce the likelihood of emails being flagged as spam.

Email marketer from Webmaster Forum mentions that using CSS to hide text (e.g., `display:none` or `visibility:hidden`) can easily trigger the LONG_INVISIBLE_TEXT rule. They advise avoiding such techniques and instead focusing on providing valuable content in a visible and accessible format.

Email marketer from StackExchange explains that sometimes legitimate emails can trigger the DMARC_REJECT rule if there are misconfigurations in DNS records or temporary issues with authentication. It's important to verify the SPF and DKIM records are correctly set up and that the sending server is authorized.

Expert and Email marketer from Email Geeks discuss DMARC_REJECT rules in SpamAssassin. Steve clarifies DMARC_REJECT is a standard rule in SpamAssassin, whereas Crystal indicates her host uses a custom set potentially overriding the standard rules with a KAM_ prefixed version from McGrail Foundation. Steve suggests the custom rules may have different weighting or simply be included in the custom set, but the behavior sounds identical.

Expert from Spamresource.com explains that SpamAssassin's scoring system is designed to identify characteristics commonly associated with spam. Even if a particular rule seems counterintuitive (like DMARC reject getting a positive score), it's because the rule is intended to identify potential abuse patterns when combined with other indicators.

Expert from Email Geeks explains that the default DMARC_REJECT score for non-bayesian scoring is 0.001, a score to simply record the event.

Expert from Word to the Wise responds that invisible content triggers spam filters because it attempts to deceive the reader and/or the filter. This includes text in small font, hidden with CSS, or the same color as the background. It's a common spam technique to hide links or keywords.

Documentation from Apache SpamAssassin Wiki explains that the DMARC_REJECT rule is triggered when an email has a DMARC policy of reject but fails authentication checks like DKIM or SPF. A positive score is assigned because the sender is explicitly telling the recipient to reject unauthenticated mail, and the fact that it's being evaluated means it might be a forgery attempt.

Documentation from MailChannels explains SpamAssassin assigns scores based on a variety of rules, with higher scores indicating a higher likelihood of being spam. While a single rule like DMARC_REJECT may have a low score, it contributes to the overall score which determines if an email is flagged as spam.

Documentation from SpamAssassin Source Code explains that the MIME_NO_TEXT rule checks for multipart MIME emails that lack a plain text part. This can be a sign of spam, as legitimate emails usually include a plain text version for compatibility. A positive score is assigned because spammers often prioritize HTML content and neglect plain text alternatives to evade text-based spam filters.

Documentation from SpamAssassin Source Code explains that the LONG_INVISIBLE_TEXT rule detects excessive amounts of text hidden using techniques like small font sizes or colors matching the background. A positive score is assigned because this is a common tactic used by spammers to hide keywords or links from users while still being indexed by search engines.