Why am I seeing Gmail SPF error messages and how do I fix it?
Matthew Whittaker
Co-founder & CTO, Suped
Published 23 May 2025
Updated 17 Aug 2025
10 min read
Receiving a Gmail SPF error message can be a frustrating experience. It often looks like a message saying that mail has been rate-limited because SPF does not pass, or that Gmail requires all large senders to authenticate with SPF. This can happen even if your SPF record looks correct and other mailboxes (like Yahoo) are receiving your emails with a spf=pass result. Google has become increasingly strict with its email authentication requirements, so understanding these errors is crucial for maintaining email deliverability. This goes beyond just having an SPF record; it's about ensuring its proper configuration and alignment with other authentication protocols like DKIM and DMARC. When SPF fails, your emails are much more likely to land in spam folders or be outright rejected, directly impacting your communication with recipients. Fixing email deliverability is critical for business operations.
The message about rate limiting due to SPF not passing indicates that Google's systems are seeing a high volume of mail from your sending infrastructure that isn't properly authenticated according to your SPF record. This isn't necessarily a permanent block, but a warning that your emails might be delayed or sent to spam if the issue persists. Google prioritizes authenticated mail, and when SPF fails, it raises a red flag, leading to stricter filtering. Errors like these signify that your sending practices aren't fully aligning with Gmail's sender guidelines.
Even if your SPF record seems correct and passes for other providers, Gmail might encounter issues due to specific interpretations or additional checks. One common cause is exceeding the 10 DNS lookup limit for SPF records, which can lead to a PermError or TempError. Another issue arises when an included DNS record (like an MX record) within your SPF record fails to resolve properly, which happened to one user in a Server Fault discussion. Email forwarding can also complicate SPF validation, as the forwarding server might change the sending IP, causing the original SPF record to fail authentication.
The core of the problem often lies in SPF alignment or the complexity of your sending infrastructure. If you use multiple services to send email (e.g., your own server, a marketing platform, a transactional email API), each one must be explicitly authorized in your SPF record. If even one is missed or incorrectly listed, Gmail might flag your email as unauthenticated. This is especially relevant for Google Workspace users who might have their SPF records misconfigured, as highlighted in Google's own troubleshooting guide.
Key factors for SPF success with Gmail
Comprehensive Authorization: Ensure your SPF record includes all IP addresses and domains that send email on your behalf, including third-party services like marketing platforms or CRMs.
DNS Lookup Limits: Avoid exceeding the 10 DNS lookup limit. Consolidate your SPF record if necessary, potentially using an SPF flattening service to manage multiple include mechanisms.
Proper DNS Resolution: Verify that all domains and MX records referenced in your SPF record resolve correctly and are accessible to Gmail's systems.
DMARC Implementation: While SPF is foundational, DMARC provides enforcement and reporting, helping you monitor and improve your authentication posture, and is now a requirement for bulk senders to Gmail.
Common causes of SPF failures with Gmail
Several common issues can lead to SPF failures with Gmail, even when your record appears valid. One primary culprit is an incorrect SPF record syntax or an SPF record that is split across multiple TXT records, which can confuse receiving servers. When you have multiple SPF records for a single domain, it invalidates your SPF, leading to a PermError, rather than a SoftFail or Fail. This can result in emails being blocked or sent to the spam folder. Another frequent issue is exceeding the 10-DNS-lookup limit imposed by SPF. Each include, a, mx, and ptr mechanism in your SPF record counts as a lookup. If you have too many, your SPF record will produce a PermError, causing authentication failure.
Another often-overlooked cause is that your SPF record might be missing authorized sending sources. Many businesses use various email service providers (ESPs), marketing automation platforms, or CRM systems to send emails. Each of these platforms needs to be explicitly listed in your SPF record. If an email is sent from a server or service not authorized by your SPF, it will fail the check. This is particularly relevant for SendGrid users, for example, whose transactional emails might get flagged if their SPF isn't correctly configured to include SendGrid's sending IP addresses. A final common cause is a DNS resolution issue for included mechanisms, especially the mx or a mechanisms. If the A record for your MX server fails to resolve, Gmail will not be able to verify the legitimacy of the sending server, leading to an SPF error.
Here's an example of an SPF record that includes various common sending sources. Note that this record is for illustrative purposes and should be adapted to your specific setup.
This record allows Google Workspace, SendGrid, your custom mail server (mail.yourdomain.com), and a specific IP address (192.0.2.1) to send emails on your domain's behalf. The -all mechanism indicates a hard fail, meaning any other sender not listed should be rejected. This strict policy helps protect your domain from spoofing and improves your sending reputation. However, ensure all legitimate senders are included, or your emails will be blocked.
Diagnosing the problem
Diagnosing SPF issues requires a methodical approach. Start by checking the email headers of messages that failed to deliver to Gmail. Look for the Authentication-Results header, which will provide details on SPF, DKIM, and DMARC checks. A spf=fail or spf=temperror result here is a clear indicator. You can manually inspect these headers or use an email analyzer tool like AboutMy.email, which can provide a comprehensive report on your email's authentication status, including SPF, DKIM, and DMARC. This tool was instrumental in helping a user in a recent discussion on Slack identify an MX record DNS lookup failure as the root cause of their SPF issues. Understanding the email authentication results in your email headers is a fundamental skill for troubleshooters.
Next, consult your DNS records directly. Use a DNS lookup tool to verify your SPF TXT record. Pay close attention to any include mechanisms and ensure they do not exceed the 10 DNS lookup limit. If they do, you'll need to flatten your SPF record or consolidate included domains where possible. Also, check the DNS resolution for any a and mx mechanisms present in your SPF record to ensure they resolve to valid IP addresses. A failing MX record A record, for instance, can lead to SPF TempError or PermError statuses when Gmail attempts to validate your sending domain.
Manual Header Analysis
Process: Access the raw headers of a failed email (e.g., in Gmail, Show original). Look for Received-SPF and Authentication-Results lines.
Pros: Direct insight into the recipient server's SPF verdict. No external tools needed.
Cons: Requires technical understanding of email headers. Can be time-consuming for complex issues. Doesn't check your DNS configuration.
Using Email Analyzer Tools
Process: Send an email to a dedicated address provided by the tool (e.g., AboutMy.email). The tool analyzes headers and DNS records to provide a detailed report.
Cons: Relies on external services. Might not capture every nuanced issue immediately.
Steps to fix Gmail SPF errors
Once you've identified the root cause of your Gmail SPF errors, it's time to implement the fixes. The first step is to carefully review and update your SPF TXT record. Ensure that all IP addresses and domains that send emails on your behalf are accurately listed. This includes your own mail servers, cloud-based email services, transactional email providers, and marketing automation platforms. Be meticulous, as even missing one legitimate sender can lead to deliverability issues. Double-check for any typos or incorrect syntax, as these can invalidate your entire SPF record.
If you're hitting the 10-DNS-lookup limit, consider flattening your SPF record. This involves replacing multiple include mechanisms with the actual IP addresses they resolve to, reducing the number of DNS queries. Several online tools can help with SPF flattening. For DNS resolution problems, contact your DNS provider to resolve any issues with A or MX records that your SPF references. Ensure they are correctly configured and publicly resolvable. These fundamental DNS settings are critical for email authentication.
Finally, beyond SPF, ensure you have correctly implemented DKIM and DMARC for your domain. DKIM (DomainKeys Identified Mail) provides a cryptographic signature that verifies the sender's identity and that the message hasn't been tampered with in transit. DMARC (Domain-based Message Authentication, Reporting & Conformance) builds on SPF and DKIM, allowing you to tell receiving mail servers what to do with emails that fail authentication (e.g., quarantine them, reject them, or simply monitor them). For bulk senders to Gmail, a DMARC policy with p=quarantine or p=reject is now mandatory. Implementing these records correctly significantly boosts your email's authenticity and deliverability, helping you avoid SPF errors and improving your domain's reputation with mailbox providers like Outlook and Gmail. If you're seeing issues with DKIM, we have a guide on how to fix DKIM failures.
Views from the trenches
Best practices
Always include all legitimate sending services and IPs in your SPF record to prevent authentication failures.
Use an SPF flattening service to stay within the 10-DNS-lookup limit if your record is complex and involves many includes.
Regularly monitor your DMARC reports to catch any SPF authentication issues as they arise and address them promptly.
Ensure DNS records for MX and A records referenced in your SPF are correctly configured and resolvable.
Common pitfalls
Having multiple SPF TXT records on a single domain, which invalidates SPF and causes emails to be rejected.
Exceeding the 10 DNS lookup limit in your SPF record, leading to a permanent error (PermError).
Forgetting to include all third-party email senders (e.g., marketing platforms, transactional email services) in your SPF record.
Not having a DMARC record, which leaves your domain vulnerable to spoofing and can impact deliverability to strict receivers like Gmail.
Expert tips
"The first thing I check is always the raw email headers, specifically the Authentication-Results line. It tells you exactly what Google thought of your SPF, DKIM, and DMARC. From there, I use a good SPF lookup tool to trace the record and see where it might be hitting the 10-lookup limit or if any included domains are failing to resolve. Often, it's a hidden DNS issue further down the chain."
"Many times, clients overlook SPF issues with internal sending systems or obscure third-party tools. Make a comprehensive list of every service that sends email on behalf of your domain, no matter how small, and ensure each one is covered in your SPF record. For enterprise environments, this can be a huge undertaking."
"While SPF is critical, don't neglect DKIM and DMARC. Gmail's recent changes mean you essentially need all three. A strong DMARC policy with reporting will give you unparalleled visibility into your email ecosystem and help you proactively catch and fix SPF failures."
"I've seen cases where the SPF record itself was technically valid, but the associated MX records were misconfigured or pointed to a server that wasn't responding correctly. This causes the SPF check to fail because the recipient server can't verify the legitimate sending source. It's not always an SPF syntax problem; sometimes it's deeper DNS hygiene."
Marketer view
A marketer from Email Geeks says they saw a huge spike in Gmail error messages where SPF did not pass, even though their SPF record looked correct and Yahoo was still receiving emails with SPF passing.
2024-04-25 - Email Geeks
Expert view
An expert from Email Geeks mentioned that it's difficult to offer speculation without seeing the actual domains and IPs involved in the email issues.
2024-04-25 - Email Geeks
Summary
Resolving Gmail SPF error messages requires a thorough review of your SPF record, ensuring all sending sources are authorized, and addressing any underlying DNS issues. It's not just about having an SPF record, but having one that is correctly configured, within DNS lookup limits, and aligned with your broader email authentication strategy including DKIM and DMARC. By systematically diagnosing and fixing these issues, you can significantly improve your email deliverability to Gmail and maintain a healthy sender reputation. Remember, consistent monitoring of your email authentication with tools like Google Postmaster Tools is key to preventing future deliverability problems and staying off email blocklists (or blacklists).
Yahoo) are receiving your emails with a spf=pass result. Google has become increasingly strict with its email authentication requirements, so understanding these errors is crucial for maintaining email deliverability. This goes beyond just having an SPF record; it's about ensuring its proper configuration and alignment with other authentication protocols like DKIM and DMARC. When SPF fails, your emails are much more likely to land in spam folders or be outright rejected, directly impacting your communication with recipients. Fixing email deliverability is critical for business operations.
Gmail's sender guidelines.
Gmail might encounter issues due to specific interpretations or additional checks. One common cause is exceeding the 10 DNS lookup limit for SPF records, which can lead to a PermError or TempError. Another issue arises when an included DNS record (like an MX record) within your SPF record fails to resolve properly, which happened to one user in a Server Fault discussion. Email forwarding can also complicate SPF validation, as the forwarding server might change the sending IP, causing the original SPF record to fail authentication.
Google Workspace users who might have their SPF records misconfigured, as highlighted in Google's own troubleshooting guide.
SendGrid users, for example, whose transactional emails might get flagged if their SPF isn't correctly configured to include SendGrid's sending IP addresses. A final common cause is a DNS resolution issue for included mechanisms, especially the mx or a mechanisms. If the A record for your MX server fails to resolve, Gmail will not be able to verify the legitimacy of the sending server, leading to an SPF error.
Slack identify an MX record DNS lookup failure as the root cause of their SPF issues. Understanding the email authentication results in your email headers is a fundamental skill for troubleshooters.
Outlook and 
