How to Check if SPF Record Has a Tag with No Value in 2026

Why Does an SPF Tag with No Value Break Your Email Delivery?

You send emails. Your team trusts the deliverability. Then comes a wave of hard bounces. No warning. No clear cause. You check the logs, scan your DNS—everything looks fine. But your messages still don’t land in inboxes.

Here’s a silent killer: an SPF record with a tag that has no value. Not a typo, not an extra space. Just a tag like include: with no domain after it. That single omission breaks SPF validation across major mail servers. And because the syntax appears correct, most tools won’t flag it.

SPF is meant to verify that your email comes from an authorized server. But if your record has include: with no domain, it’s like showing up at a door with a key that belongs to a house you didn’t define. The gate won’t open—not because the key is wrong, but because it's unassigned.

Key takeaways

• An SPF record with a tag like include: without a domain is technically invalid and will cause hard bounces.
• Mail servers reject messages when an SPF record contains a tag with no value, leading to deliverability failure even if the syntax appears correct.
• Standard DNS validators often miss missing tag values—only check syntax—so you must manually audit SPF records for completeness.

What Does 'SPF Record Has a Tag with No Value' Actually Mean?

If your SPF record includes a tag like include: without a domain value—e.g., include: instead of include:_spf.example.com—it’s invalid. Receiving servers reject such records because tags must have a defined value. An empty tag breaks SPF syntax, leading to failed authentication and potential delivery issues.

Tags Must Be Paired with Values

SPF uses specific tags—like include, ip4, ip6, a, or all—to define which servers are allowed to send email on behalf of your domain. Each tag must be followed by a valid value. For instance, include:_spf.google.com tells receiving servers to check Google’s SPF policy for authorization. If you write just include: with no domain, the server sees it as malformed and ignores the entire record.

Even a single missing value can cause SPF to fail. This includes tags like ip4: without an IP address or a: without a domain. The SPF specification (RFC 7208) requires a strict format. When parsing fails, the result is often a neutral or fail outcome, which hurts deliverability.

Let’s say you’ve added include: by accident during record editing. You’ll see a “SPF record has a tag with no value” error. It’s not a warning—it’s a hard syntax violation. You can’t fix this with configuration alone; you have to edit the DNS record to remove the tag or add the missing value.

How to Fix It and Avoid Recurrence

Always check your SPF record for completeness. Tools like MXToolbox’s SPF checker or RFC 7208 will flag missing values. Don’t rely on guesswork—each tag must be syntactically correct.

If you’re managing multiple domains or large email lists, manually checking every record is inefficient. You can avoid this problem by using an email verification tool to validate addresses and detect issues before sending. For instance, MailTester’s bulk verification checks both syntax and deliverability, helping you catch invalid sender policies indirectly by identifying misrouted or undeliverable emails early.

How to Check if Your SPF Record Has a Tag with No Value

You can check if your SPF record has a tag with no value by retrieving your domain’s SPF record via DNS lookup, then scanning it manually for tags like include: or all without any following value. Missing values on SPF tags are invalid and can cause email delivery failures. Always test your final record using a trusted SPF validator to catch errors before they impact your sender reputation.

1. Fetch your domain’s SPF record using a DNS lookup tool like MxToolbox or DNSLookup.org. Enter your domain name, select the TXT record type, and retrieve the SPF content. This step gives you the raw data you need to inspect.
2. Examine the record line by line for incomplete tags. Look for any tag that appears without a value—such as include: with no domain following it, or all with no modifier. For example, include: with nothing after it is invalid and breaks SPF evaluation.
3. Check include: declarations for broken or outdated domains. Some older or poorly maintained domains may have misconfigured SPF records themselves. If a referenced domain’s SPF is broken or missing, it can cause your own record to fail, even if your syntax appears correct.
4. Validate your full SPF record using an online SPF validator. Tools like MxToolbox’s SPF Checker or SPF Check will flag malformed syntax, missing values, or unreachable include domains. This step catches errors that manual inspection might miss.
5. Ensure your SPF record is under the 10 lookup limit. Each include: or redirect: counts as a DNS lookup. If your record exceeds ten lookups, it will fail validation. Use a tool to simulate the chain of lookups and avoid hitting the limit.

Common Pitfalls to Watch For

Even seemingly correct SPF syntax can fail if a tag like include: has no value or points to an unreachable domain. This often happens during domain migrations or when using outdated third-party service configurations. Always verify the full chain of includes.

Why This Matters

SPF failures due to invalid tags directly impact deliverability. Inconsistent or malformed SPF records can trigger spam filters or cause senders to be blocked entirely. Fixing these issues ensures your emails reach inboxes reliably.

For teams running regular email campaigns, using a service like MailTester’s bulk verification can help catch issues across your entire list before sending—ensuring SPF and other delivery risks are minimized at scale.

SPF Record Tags and Their Required Values

You must ensure every SPF record tag includes a required value: include: needs a domain, ip4: and ip6: need valid IP addresses, all requires a qualifier like ~all or +all, and a: or mx: should reference a domain if used. Tags without values break SPF validation and hurt deliverability.

SPF Tag Requirements by Type

Let’s break down what each tag expects. If a tag is missing its required value, the record is invalid and email may be rejected. The SPF specification (RFC 7208) defines these precisely.

The SPF specification is published by the IETF as RFC 7208. You can review it directly at tools.ietf.org/html/rfc7208 — it’s the authoritative source for every tag’s behavior.

Even small mistakes—like omitting a domain from include: or a qualifier from all—can trigger strict filtering by receiving servers. This leads to bounces, lower inbox placement, or outright deliverability loss.

Use a real-time email verification tool like MailTester’s email checker to catch invalid addresses before sending. For bulk lists, verify entire domains with bulk verification to ensure your sender infrastructure is clean and compliant.

Common SPF Mistakes That Lead to Tag-Without-Value Errors

Many SPF issues stem from copying incomplete snippets, using outdated templates, or trusting UI tools that skip validation. A tag like include: without a domain or ip4: without an IP address triggers a "tag without value" error during DNS validation. These mistakes often break email authentication and lead to delivery failures. Let’s go through the most common pitfalls you should avoid.

Copy-Paste Without Validation

• Don’t copy SPF snippets from forums or old docs without checking every tag’s value. A include: tag without a domain (e.g., include:) is invalid and will cause a DNS rejection.
• Verify the full value after each tag. Missing spaces, typos, or orphaned tags like all or redirect: without a value are frequent causes of SPF parsing errors.
• Use a tool like MXToolbox to test your SPF record syntax before publishing—it checks for missing values and common miswrites.

Outdated Templates and UI Glitches

• Old SPF templates often include include:_spf.example.com but forget to replace the placeholder with the actual domain. Always verify the full value when using any template.
• Many DNS UIs allow saving records without validating syntax. You might add an include: tag with no domain, and the system won’t warn you. This results in a blank value, which violates RFC 7208.
• Nested include: chains can fail silently if one link returns no value. If include:thirdparty.com resolves to nothing, the entire chain fails at that point.
• Test each include chain individually. Use SPF Checker by DMARC Analyzer to trace how your record resolves and flag missing values.

These are not theoretical edge cases—many senders discover SPF errors only after their emails are blocked. Preventing tag-without-value errors starts with treating SPF like code: every tag must have a proper, valid value, or it breaks authentication.

How MailTester Helps You Detect and Fix SPF-Related Issues

You can’t directly check SPF records with MailTester, but it detects whether emails fail to deliver due to misconfigured SPF policies. When your message is rejected by the recipient’s mail server because of an invalid SPF record, MailTester flags it as a delivery failure or rejection—helping you trace the issue to sender policy errors without needing to parse DNS yourself. This real-world validation is more reliable than theoretical checks.

Real-World Verification, Not DNS Spot Checks

SPF records are hard to read and easy to break. A missing value in a tag like include or all can cause a validation failure even if the record looks syntactically correct. MailTester doesn’t scan DNS records—it checks what actually happens when a message reaches the inbox. If sending to an address fails due to an SPF issue, the result appears in your verification report as a rejection, often with a clear reason like “rejected due to SPF policy” or “sender policy mismatch.”

Let’s say you’re running a campaign and notice high bounce rates with no clear pattern. Using MailTester’s bulk list verification, you can test your entire list and see which emails are being blocked—not just because they’re invalid, but because the sending domain’s SPF policy doesn’t allow delivery. This filters out false positives and focuses your effort on actual deliverability issues.

Pinpointing the Problem with Bounce Analysis

After a verification run, you get a detailed report showing every email’s status. Addresses flagged as “rejection” or “delivery failure” can be filtered out or investigated further. By analyzing the bounce reasons and cross-referencing them with your sender policy, you can spot patterns—like a sudden spike in failures from domains that share the same SPF configuration.

For example, if your marketing campaign starts failing across multiple domains, and MailTester reports consistent SPF-related rejections, it signals a misconfigured include or mechanism in the SPF record. This helps you avoid blaming the mailing list and instead fix the root cause. You can also use MailTester’s API to programmatically verify individual addresses before sending, reducing the chance of policy violations early in the workflow.

For teams using tools like Klaviyo, HubSpot, or SendGrid, MailTester’s integrations allow you to test delivery health in real time. You’re not just checking if an address exists—you’re checking whether it receives email under real conditions. This is how you catch SPF issues before they hurt engagement.

Learn how to validate your entire email list: verify your list with MailTester. If you want to test individual addresses before sending, use the email checker. For high-volume senders, the verification API handles checks at scale.

SPF configuration is complex, and small errors have big consequences. MailTester doesn’t replace DNS tools like MxToolbox, but it shows you whether those errors actually matter—to your inbox placement and delivery results. As outlined in RFC 7208, SPF is part of a layered authentication system. Validating sender policy compliance at scale? That’s the practical next step.

Real-Time Verification Reveals SPF Issues Without DNS Access

You don’t need to dig into DNS records to spot SPF problems. MailTester’s real-time verification API and bulk list checks detect delivery failures caused by SPF misconfigurations—like a 550 5.7.1 reject—by analyzing actual server responses. This works even if the SPF record appears valid on paper.

See the Real-World Impact of SPF Configurations

Let’s say your SPF record includes a include tag with a missing or incorrect value. The record might pass a basic DNS validator, but real mail servers will still reject it. That’s where MailTester’s verification process shines: it sends test messages to actual receiving servers and reports back exactly why delivery failed.

You’re not guessing. You’re seeing the raw bounce codes and server feedback that signal trouble. For instance, a 550 5.7.1 response—commonly seen in Microsoft 365 and Gmail systems—often points to an SPF policy violation, even when the DNS record looks syntactically correct. Without live testing, these issues go unnoticed.

This is especially valuable when managing large email lists. Running a bulk verification through MailTester’s API lets you scan thousands of addresses in minutes. The result? A list of addresses with clear verdicts—such as “rejected by server”, “risky”, or “valid”—each backed by actual delivery data.

SPF isn’t just about syntax. It’s about how servers interpret it in practice. A record that passes DNS-level checks may still block inbound mail if it lacks proper mechanisms, uses invalid includes, or exceeds the 10 lookup limit. These are edge cases that testable delivery results catch.

According to the IETF’s SPF specification, receiving servers must reject messages from domains with invalid or misconfigured SPF policies. But that doesn’t mean every tool checks for all edge cases. MailTester focuses on actual delivery behavior, not just DNS syntax.

Automate Detection Without Manual DNS Checks

Instead of manually reviewing SPF records or relying on static tools, use MailTester’s real-time verification. The API gives you a live test of how each address performs. You can integrate this with your email platform (like Mailchimp, HubSpot, SendGrid) via the official integrations, so invalid addresses never make it to your campaign.

Even a single address flagged with a “rejected by server” verdict and a bounce code like 550 5.7.1 can indicate a deeper SPF issue in your domain configuration. You can catch these before they hurt sender reputation or trigger blocklists.

How to Fix an SPF Record with a Missing Tag Value

If your SPF record has a tag like include: without a value—such as include: instead of include:spf.sendgrid.net—it’s invalid and can break email deliverability. SPF requires every tag to have a properly formatted value. Fix it by adding the correct domain name after the tag, then validate it using a trusted tool. Once updated, allow up to 48 hours for DNS changes to propagate before testing again.

Identify and Correct the Invalid Tag

1. Inspect your SPF record for tags like include:, ip4:, or all that lack a value. An entry like include: is syntactically incorrect and will cause validation failures.
2. Check your email service provider’s documentation—such as SendGrid, Mailchimp, or Amazon SES—to find the correct domain or IP to reference. For example, if you use SendGrid, the proper value is spf.sendgrid.net.
3. Update the record to include the full domain. Replace include: with include:spf.sendgrid.net, making sure there are no missing spaces or syntax errors. Proper syntax is essential; SPF is strict about formatting.

Verify the Fix with Trusted Tools

After updating, test the record using an industry-standard validation tool. The MXToolbox SPF Checker analyzes syntax and can detect missing values, duplicate tags, or oversized records—common issues that break SPF.

• Enter your domain name to check the current SPF record.
• Review the output for warnings like "Tag has no value" or "Invalid syntax." Fix anything flagged.
• Once resolved, retest to confirm the record now passes validation.

After DNS propagation—up to 48 hours—verify delivery stability by sending test emails through your system and using a real-time deliverability tester. MailTester’s inbox placement test checks whether emails land in the inbox, spam folder, or are blocked entirely. It’s the only way to confirm that your SPF fix didn’t introduce new issues.

When SPF Problems Are Really Indicators of Bigger Deliverability Risks

When an SPF record has a tag with no value, it's not just a technical misstep—it’s a sign that your email infrastructure may be inconsistently managed. Such errors often point to broader issues like outdated DNS records, unverified sending sources, or misaligned authentication practices. Left unaddressed, they increase the risk of being flagged by spam filters, landing in spam folders, or outright blocked. This isn’t just about fixing a single tag—it’s about recognizing that email authentication is part of a larger deliverability ecosystem.

SPF Errors Are Symptoms, Not the Disease

Just because you’ve fixed a missing tag value doesn’t mean your deliverability is secure. An SPF record with syntax issues often shows up in environments where other authentication mechanisms are also misconfigured. For example, DKIM might be missing, DMARC policies might be set to reject without monitoring, or you may be sending from a domain that hasn’t been properly authorized in your ESP. It’s rare for one flaw to exist in isolation.

When infrastructure is managed carelessly, spam traps are more likely to be triggered. Email receivers like Gmail, Yahoo, and Outlook use reputation signals that combine authentication, engagement, and bounce history. A single malformed SPF record may not block your messages today—but it makes your domain look less trustworthy in the eyes of their filters. According to RFC 7208, SPF records are meant to be unambiguous; failing that can lead to inconsistent evaluation and higher rejection rates.

Go Beyond the Immediate Fix

Fixing the immediate SPF issue is necessary, but not enough. You need to verify that your full email stack is aligned. Use tools to test how your messages land in real user inboxes—not just whether they pass technical checks. MailTester’s Inbox Placement Tester simulates delivery across major providers, giving you a clear picture of how your emails are perceived in actual inboxes.

Combine this with regular list hygiene. Over time, email addresses decay. Invalid, disposable, or dormant addresses hurt your sender reputation and inflate your bounce rate. Before sending, check each address using a real-time verification tool—like MailTester’s email checker—to catch problems early. For bulk sends, bulk list verification helps you identify risky addresses before they impact deliverability.

Think of SPF as one thread in a web. A loose thread might not collapse the whole structure, but it weakens it. Fixing it helps, but true reliability comes from inspecting every part. Regular testing, clean lists, and proper authentication aren’t optional—they’re foundational.

Use MailTester for Proactive Deliverability and SPF Validation

You can check if an SPF record contains a tag with no value by validating the DNS record structure using a DNS lookup tool or an email verification service like MailTester. It identifies syntax errors like missing values in mechanisms (e.g., include: without a domain) or malformed qualifiers. The service flags these issues before they cause delivery failures.

Test real inbox delivery with inbox placement testing

• Run inbox placement tests to simulate how your email lands in Gmail, Outlook, Apple Mail, and Yahoo—real inboxes, real filters, and real spam scoring.
• Each test checks deliverability through multiple layers of authentication, including SPF, DKIM, and DMARC, helping you catch issues like missing or malformed tags before sending to real recipients.
• MailTester’s inbox placement tester uses actual inbox environments, not just SPF validators, so you don’t get false positives from outdated or incomplete validation tools.

Integrate with your tools and automate verification

• Connect MailTester to Mailchimp, SendGrid, or HubSpot using the official integrations to automatically verify every new subscriber before adding them to your campaign list.
• Use the real-time verification API to check addresses on your web forms, dashboards, or CRM without slowing down user sign-ups.
• Check individual addresses with the email checker when you suspect an issue or need to validate a single recipient quickly.

When you run a check, MailTester doesn’t just report “valid” or “invalid.” It dives into why—flagging issues like SPF tags with no value, missing DNS records, or catch-all domains. You’re not guessing. You’re diagnosing.

Spam filters use strict rules. A malformed SPF record—like include:example.com without any domain—won’t be processed correctly. The SPF spec (RFC 7208) requires every mechanism to have a complete, resolvable value. MailTester catches these errors early.

Get smart help with the in-app AI assistant

• Use the in-app AI assistant to parse verification results and explain what “SPF error: tag has no value” means in plain English.
• Get actionable steps—not just “invalid”—like “Add a domain to your include: tag” or “Remove an empty mechanism.”
• Automatically detect patterns in your list: if many addresses fail SPF validation, it may signal broader sender reputation issues.

Start for free with 100 email verifications—no credit card needed. You can test your entire list or validate individual addresses. Credits never expire, so there’s no pressure to use them fast.

See pricing details and upgrade when ready.

Final Takeaway: Fixing SPF Tags with No Value Starts with Verification

An SPF record with a tag that has no value is invalid by protocol. It breaks DNS parsing, triggers rejection at the receiving end, and causes delivery failure—regardless of other settings.

You cannot reliably detect these issues through static checks alone. A domain may pass DNS validation tools but still fail in real-world sends due to hidden syntax flaws like empty tags.

How to confirm the impact

• Test actual email sends to real addresses using inbox placement tools.
• Use email verification APIs to catch invalid addresses before sending.
• Check for syntax anomalies like include: with no domain or all with no modifier.

Deliverability isn’t just about content or sender reputation. It starts with clean, valid DNS records that survive the full SMTP handshake.

Sources

• 52.1% of the world's top 1.8 million domains (937,931 domains) now publish a valid DMARC record, up from 29.1% in 2023. — EasyDMARC 2026 DMARC Adoption & Enforcement Report (2026)
• Google reported 265 billion fewer unauthenticated messages sent to Gmail users in 2024 — a 65% reduction — after its bulk-sender rules took effect, with 500,000+ top domains publishing DMARC records in response. — Google (via MailOver bulk-sender requirements guide) (2024)

Keep reading

• Email authentication: SPF, DKIM, DMARC, BIMI and MTA-STS (complete guide)
• Check DKIM Signature Expiration Status Before Sending Emails
• Why Does My SPF Record Fail to Cover Used Sending IP Range?
• Fix DMARC Alignment Failure 550 5.7.1 Email Deliverability Issues
• How IP Address Whitespace Impacts SPF ip4 Mechanism Compliance

Ready to put this into practice? MailTester verifies emails with 98.9% accuracy — start with 100 free verifications.

Frequently asked questions

Can a missing value in an SPF tag cause an email to be rejected?

Yes. A malformed SPF record—even with one tag missing its value—can cause receiving servers to reject messages outright, especially if they enforce strict SPF validation.

How do I know if my SPF record is valid?

Use a DNS validation tool like MxToolbox, or send test emails through MailTester to check whether they are delivered or rejected due to SPF errors.

Does SPF validation affect all email senders?

Yes. All outbound emails are subject to SPF checks when the receiving server enforces it. A flawed record can impact campaigns, newsletters, and transactional messages alike.

Can I fix my SPF record without technical help?

Yes, if you identify which tag is missing its value. Most email providers list valid SPF syntax for their services, making corrections straightforward.

Why don’t all SPF validators catch missing tag values?

Some tools only check syntax structure. A tag like `include:` appears syntactically valid until you inspect whether it has a referenced domain. Real-world delivery testing is needed.

Is there a limit to how many entries an SPF record can have?

Yes. The SPF record must be under 255 characters and can include no more than 10 DNS lookups to prevent excessive query load.

How long does it take for an SPF change to take effect?

DNS changes typically propagate within 24 to 48 hours. Testing should wait until propagation completes.

Does MailTester check SPF records directly?

No. MailTester doesn’t inspect DNS records, but it detects failures caused by SPF issues during real-time email verification.

Can a catch-all email account mask SPF issues?

Yes. A catch-all can accept messages even if SPF fails, which may hide delivery problems until you send to real, unique addresses.

Is SPF still required with DMARC and DKIM?

Yes. SPF remains a foundational component of email authentication. While DMARC and DKIM add layers of security, SPF is still widely enforced.

What’s the best way to prevent SPF-related bounces?

Use MailTester to verify email addresses before sending, test deliverability across real inboxes, and review DNS records using tools like MxToolbox.

Can a typo in an SPF domain cause a tag to be value-less?

Not directly. But a typo in a domain (e.g., `include:spf.examples.com`) can make the lookup fail, resulting in a missing value during evaluation.