--- title: "Why do legitimate emails fail SPF checks sometimes? | AutoSPF" description: "It’s common for legitimate emails to be falsely marked as spam or rejected because they failed the SPF verificationchecks." image: "https://autospf.com/og/blog/why-do-legitimate-emails-fail-spf-checks-sometimes.png" canonical: "https://autospf.com/blog/why-do-legitimate-emails-fail-spf-checks-sometimes/" --- Quick Answer It’s common for legitimate emails to be falsely marked as spam or rejected because they failed the SPF verificationchecks. While this is not a one-off occurrence, it does leave room for missed conversations, which can lead to reputational and financial damages. ## Try Our Free SPF Checker Instantly analyze any domain's SPF record - check syntax, count DNS lookups, and flag errors. [ Check SPF Record → ](/tools/spf-checker/) Share [ ](https://www.linkedin.com/sharing/share-offsite/?url=https%3A%2F%2Fautospf.com%2Fblog%2Fwhy-do-legitimate-emails-fail-spf-checks-sometimes%2F "Share on LinkedIn") [ ](https://twitter.com/intent/tweet?text=Why%20do%20legitimate%20emails%20fail%20SPF%20checks%20sometimes%3F&url=https%3A%2F%2Fautospf.com%2Fblog%2Fwhy-do-legitimate-emails-fail-spf-checks-sometimes%2F "Share on X/Twitter") [ ](https://www.facebook.com/sharer/sharer.php?u=https%3A%2F%2Fautospf.com%2Fblog%2Fwhy-do-legitimate-emails-fail-spf-checks-sometimes%2F "Share on Facebook") [ ](https://reddit.com/submit?url=https%3A%2F%2Fautospf.com%2Fblog%2Fwhy-do-legitimate-emails-fail-spf-checks-sometimes%2F&title=Why%20do%20legitimate%20emails%20fail%20SPF%20checks%20sometimes%3F "Share on Reddit") [ ](mailto:?subject=Why%20do%20legitimate%20emails%20fail%20SPF%20checks%20sometimes%3F&body=Check out this article: https%3A%2F%2Fautospf.com%2Fblog%2Fwhy-do-legitimate-emails-fail-spf-checks-sometimes%2F "Share via Email") ![legitimate emails](https://media.mailhop.org/autospf/images/2025/01/kitterman-spf-1.jpg) It’s common for [legitimate emails](https://www.usatoday.com/story/tech/2021/08/23/gmail-spam-filter-email-inbox-google/8242847002/) to be falsely marked as spam or rejected because they failed the SPF verificationchecks. While this is not a one-off occurrence, it does leave room for missed conversations, which can lead to reputational and financial damages. [SPF](/blog/what-is-spf-email-a-guide-to-sender-validation-technology/) is a strong tool against phishing and [spoofing emails](https://www.pcmag.com/news/nsa-warns-of-north-korean-hackers-spoofing-emails-from-legit-domains) sent from your domain, but in some scenarios, genuine emails might not be placed in the recipients’ mailboxes. For a complete walkthrough of every SPF error type, see our [SPF Errors and Troubleshooting Guide](/blog/spf-errors-troubleshooting-guide/). This blog shares what these scenarios are and how to manage them to avoid unintended consequences. ## Possible reasons for false positives in SPF ### Incomplete SPF records If your domain’s [SPF record](/spf-record-checker/create-spf-record/) doesn’t list all the authorized servers, genuine emails sent by you will be flagged. _So, ensure that you make a holistic list of all the IPs and servers allowed to be used to send emails on behalf of your brand_. Then, whenever you introduce a new IP or server for your business, add it to your SPF record. ### Dynamic IP addresses or third-party services Emails from dynamic IPs that are not listed in the SPF record may be treated as unauthorized. Similarly, emails sent through [third-party services](https://securityscorecard.com/blog/what-is-a-third-party-service-provider/) can be flagged if their IPs are not properly included in the SPF record. Additionally, if the [SPF lookup limit](/spf-too-many-dns-lookups/spf-lookup-limit/) of 10 is exceeded, some valid entries might be skipped, causing legitimate emails to fail authentication. ![Email forwarding](https://media.mailhop.org/autospf/images/2025/01/sender-policy-framework-office-365-2167.jpg) ### Email forwarding When an email is forwarded, the forwarder’s server often resends the email using its own [IP address](https://www.investopedia.com/terms/i/ip-address.asp) instead of the original sender’s IP. During SPF verification, the recipient’s [mail server](https://www.cloudflare.com/learning/email-security/what-is-a-mail-server/) checks whether the forwarder’s IP is authorized in the SPF record of the originalsender’s domain. Since the forwarder’s IP is usually not included in the original sender’s SPF record, the SPF check fails, causing the email to be flagged as unauthorized, even though it was forwarded legitimately. ### Changes in infrastructure If you have switched to a new [email service provider](https://www.activecampaign.com/glossary/email-service-provider) or added/removed mail servers and your SPF record is not updated, some legitimate emails may be [marked as spam](https://pressgazette.co.uk/publishers/digital-journalism/facebook-spam-posts-independent-small-news-publishers/) or bounce back. ### Misconfigured SPF records If you haven’t used the right syntax in your DNS SPF record or it has spelling errors, there will be chances of false positives. _To avoid this, frequently run your SPF record through a lookup tool to learn and fix the issues before they become exploitable vulnerabilities_. ## Overcoming SPF’s shortcomings with DMARC When you implement SPF with [DKIM](/10-reasons-for-regular-spf-record-checks-in-cybersecurity/dkim-record-check/) and DMARC, your domain’s security posture improves. DMARC helps overcome SPF’s shortcomings with its reporting feature that sends domain owners feedback reports on how their emails are authenticated. It also helps with email forwarding issues where SPF usually falls short. ![domain’s security posture](https://media.mailhop.org/autospf/images/2025/01/sender-policy-framework-office-365.png) _With DMARC, domain owners set the rules for handling such emails_. Using DMARC to address SPF’s shortcomings improves [email security](/) by offering alignment and reporting features to combat spoofing and phishing. DMARC ensures that the ‘From’ domain matches the domain authenticated by SPF or DKIM. Moreover, [DMARC](/10-reasons-for-regular-spf-record-checks-in-cybersecurity/dmarc-record-check/) lets domain owners tell receiving servers how to handle emails that fail SPF orDKIM checks, allowing for more customized and effective [email authentication](/spf-too-many-dns-lookups/spf-lookup/). This prevents email-based [phishing and spoofing](https://www.bleepingcomputer.com/news/google/google-now-blocks-spoofed-emails-for-better-phishing-protection/). ## Topics [ DKIM ](/tags/dkim/)[ DMARC ](/tags/dmarc/)[ email security ](/tags/email-security/)[ SPF ](/tags/spf/)[ SPF record ](/tags/spf-record/) ![Brad Slavin](https://media.mailhop.org/autospf/images/authors/brad-slavin.jpg) [ Brad Slavin ](/authors/brad-slavin/) General Manager Founder and General Manager of DuoCircle. Product strategy and commercial lead for AutoSPF's 2,000+ customer base. [LinkedIn Profile →](https://www.linkedin.com/in/bradslavin) ## Ready to get started? Try AutoSPF free — no credit card required. [ Book a Demo ](/book-a-demo/) ## Related Articles [ Intermediate 3m 3 points to consider before setting your SPF record to -all (HardFail) May 22, 2025 ](/blog/3-points-to-consider-before-setting-your-spf-record-hardfail/)[ Intermediate 5m Are Your SPF and DKIM Identifiers Aligned? Jul 18, 2024 ](/blog/are-your-spf-and-dkim-identifiers-aligned/)[ Intermediate 6m Automated Solutions for Preventing Email Spoofing May 7, 2026 ](/blog/automated-solutions-for-preventing-email-spoofing/)[ Intermediate 7m AutoSPF Explains: The Definitive Guide to Adding an SPF Record to Cloudflare Jan 7, 2026 ](/blog/autospf-definitive-guide-adding-spf-record-cloudflare/) ```json {"@context":"https://schema.org","@type":"Organization","@id":"https://www.wikidata.org/wiki/Q138897474","name":"AutoSPF","url":"https://autospf.com","logo":{"@type":"ImageObject","url":"https://autospf.com/images/autospf-logo.png"},"description":"Automatic SPF flattening and email authentication management. 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