Gmail SPF rejection

Fix Gmail 550 5.7.24 suspicious SPF record

Gmail returns 550 5.7.24 when it considers one or more entries in the sending domain's SPF record suspicious. Inspect the selected policy and its reachable DNS dependencies before deleting or replacing anything.

Problem description

Gmail rejects the message with a response similar to:

550 5.7.24 The SPF record of the sending domain has one or more suspicious entries.

Check the current SPF configuration

What MailFixIt can test: current SPF selection, syntax, reachable include/redirect dependencies, loops, unreachable terms, void lookups and a supplied IP/MAIL FROM path. It cannot reproduce Gmail's historical DNS view or every private policy signal.

Is this temporary or permanent?

550 is permanent for this delivery attempt. Repeating the unchanged message is not expected to help. Correct a confirmed SPF or sender-path problem, then send a new message.

What this Gmail error means

This is more specific than a generic SPF failure, but the error still does not identify the exact term to remove. The selected SPF policy may contain malformed syntax, conflicting records, an unsafe authorization, a broken dependency or a structure Gmail does not accept. The message's envelope MAIL FROM domain—not necessarily the visible From domain—determines where SPF is evaluated.

Probable causes

Multiple SPF policies: more than one TXT record begins with v=spf1 at the evaluated owner.
Malformed or unsafe terms: a token is invalid, an authorization is overly broad, or the policy ends in an unsafe result.
Broken reachable dependency: an include or redirect target has no selectable SPF policy or returns a DNS error.
Unnecessary complexity: old services, unreachable terms after all, cycles or excessive lookup paths make the policy difficult to evaluate safely.
Wrong identity inspected: the root domain looks healthy while the actual MAIL FROM subdomain has a different policy.

How to diagnose it

Preserve the complete Gmail response and identify the envelope MAIL FROM domain from the bounce or message headers.
Find every TXT record at that exact domain and select only records whose first term is v=spf1.
Follow only reachable include and redirect paths. Treat timeouts as unknown rather than proof that a dependency is absent.
Inventory every legitimate sending service before removing a term.
If Gmail supplies a sender IP, evaluate that IP against the actual MAIL FROM policy.

How to fix Gmail 550 5.7.24

Correct the confirmed defect with the smallest reversible change. Consolidate duplicate SPF policies into one selected record, repair malformed terms, replace a provider dependency only with the provider's current account-specific value, and remove obsolete authorization only after ownership confirms it is unused. Do not weaken a final -all merely to make an unauthorized path pass.

After DNS changes are visible, send a fresh message through the same service and check Gmail's Authentication-Results. A syntactically valid current record does not prove the earlier message passed.

Frequently asked questions

What does Gmail 550 5.7.24 mean?

Gmail says the sending domain's SPF record contains one or more suspicious entries. Check the complete current policy and its reachable dependencies before changing it.

Should I delete an SPF include that Gmail calls suspicious?

Only after confirming that the service is no longer authorized to send. Removing a legitimate include can make valid mail fail SPF.

Can a current SPF check reproduce Gmail's rejection?

No. It can identify current public-DNS defects and evaluate a supplied sender path, but it cannot recreate Gmail's historical DNS state or every policy signal.

Related email diagnostics

Primary sources: Gmail SMTP errors and codes and RFC 7208 SPF.