Sender Policy Framework (SPF) helps receiving mail servers confirm that your email is being sent from an authorized source. When your SPF record has errors, your messages may be rejected or sent to spam, so keeping it accurate is essential.

Below are the most common SPF issues, along with recommendations to fix them.

1. Multiple SPF Records

A domain can only have one (1) SPF record. If more than one exists, mail servers can't determine which to use, and SPF validation fails.

Fix: Combine everything into a single record that starts with v=spf1.

2. Syntax Errors

SPF is sensitive to formatting. Extra spaces, missing characters, incorrect qualifiers (like using --all instead of -all), or misspelled mechanisms can break the record.

Fix: Check your record for correct syntax. Use MxToolbox's free SPF Record Check before publishing changes. Or, you can try our free SPF Record Generator tool for complete oversight.

3. Too Many DNS Lookups

SPF allows a maximum of 10 DNS lookups. Includes (include:), redirects (redirect=), and mechanisms like a or mx can quickly push you over the limit, leading to "SPF PermError" failures.

Fix: Reduce lookups or use a flattened SPF record that replaces lookups with IP addresses.

4. Missing Senders or Services

If you use third-party email services (e.g., marketing platforms, CRM tools, website forms, etc.), they must be included in your SPF record. Missing senders cause SPF failures.

Fix: List every service that sends email on your behalf using their recommended include: statement.

5. DNS Propagation Delays

When you update your SPF record, it may take 24–48 hours for DNS changes to propagate globally.

Fix: Wait before testing or sending critical email after making updates.

6. Email Forwarding

Forwarding often breaks SPF because the forwarding server's IP isn't listed as an allowed sender in your SPF record.

Fix: Encourage forwarders to use SRS (Sender Rewriting Scheme) and rely on DKIM + DMARC for authentication during forwarding.

7. Missing SPF Record

Without an SPF record, your domain has no way to prove an email was sent by you. This also leaves you vulnerable to spoofing.

Fix: Publish a basic SPF record to get started, such as:

v=spf1 -all

Then, expand it as you add legitimate, verified senders.

How to Troubleshoot and Fix SPF Problems

• Check for multiple SPF records and consolidate them.
• Validate your syntax and remove typos or formatting errors.
• Include all email senders (IPs and third-party services).
• Stay under the 10-lookup limit.
• Use an SPF validator before publishing updates.
• Update the SPF record whenever you change email providers or infrastructure.

SPF can quickly get complicated, especially as you add new tools and services. With MxToolbox Delivery Center, you can:

• Monitor SPF, DKIM, and DMARC records in one place.
• Detect lookup limit issues and syntax errors.
• Track record changes and propagation.
• Get alerts when authentication fails.

Learn more about our SPF Flattening feature