SPF alignment, as reported by services like Validity, often shows 0% even when SPF passes because the domain used for SPF authentication (the 'MAIL FROM' or envelope sender) doesn't match the domain in the 'From' header. This is a common scenario when using third-party sending services or ESPs (like Mailchimp, Constant Contact, Sendgrid, and Amazon SES) that utilize their own infrastructure and domains for sending on behalf of customers. While SPF can pass based on the ESP's domain, DMARC requires alignment between the authenticated domain and the 'From' header domain to ensure the email truly originates from the claimed sender. DMARC can pass with either SPF or DKIM alignment. If DKIM is used, the DKIM domain also needs to align for DMARC to pass. Solutions involve configuring custom MAIL FROM settings, using a custom return-path, or implementing DKIM to achieve proper alignment.

SPF alignment failures, despite SPF passing, primarily occur because the domain used for SPF authentication (MAIL FROM or return-path) does not match the domain in the 'From' header. This discrepancy is common when using third-party sending services or ESPs, which often use their own infrastructure and domains for sending emails on behalf of their customers. Although SPF can pass based on the ESP's domain, it doesn't align with the sender's domain, impacting DMARC compliance. Solutions involve configuring custom MAIL FROM settings, using a custom return-path domain, or implementing DKIM.

SPF alignment failures, even when SPF passes, stem from the domain used for SPF authentication (MAIL FROM) not matching the domain in the 'From' header. This is common with ESPs like Mailchimp, Constant Contact, Sendgrid, and Amazon SES, unless configured otherwise. SPF authenticates the sending server, but DMARC requires the domains to align. DMARC can pass with either aligned SPF or aligned DKIM. If DKIM passes but the DKIM domain doesn't align, DMARC will fail. The ultimate goal of alignment is to ensure that the authorized sending domain matches the domain displayed to the recipient.

SPF alignment fails when the domain in the 'MAIL FROM' (envelope sender or return-path) address doesn't match the domain in the 'From' header. This mismatch prevents DMARC from properly authenticating email using SPF, even if SPF passes based on the 'MAIL FROM' domain. Third-party email services often cause this issue by using their own 'MAIL FROM' domains. Alignment requires an exact match or subdomain relationship between the domains, depending on DMARC's alignment mode.