Mailybox
check dmarcdiagnose a bounce
Home / Email errors / gmail
gmail error

Gmail 552 5.7.0 — Message Blocked for Security Reasons (Attachment)

Gmail blocked the message because an attachment presents a potential security issue: a blocked file type, an executable inside an archive, or an encrypted archive it cannot scan.

Diagnose your exact bounce Email Infrastructure Digital Twin

What the bounce says

Exact wording as it appears in the rejection or NDR. Placeholders such as x.x.x.x and example.com stand for your own address and domain.

552-5.7.0 This message was blocked because its content presents a potential security issue. To review our message content and attachment content guidelines, go to https://support.google.com/mail/?p=BlockedMessage

Gmail blocks certain attachments outright: executables, scripts, and archives containing them, plus encrypted archives it cannot inspect. 552 5.7.0 is that block, and the linked policy lists the file types. The message is not delivered and will not be on retry.

Reviewed 2026-09-08. Provider wording and requirements change; the provider reference below is authoritative.

Most common causes

  • An attachment with a blocked extension such as .exe, .js, .vbs or .bat
  • An archive containing a blocked file type
  • A password-protected archive Gmail cannot inspect
  • A document with macros that match malware patterns

What to verify next

  1. Read the blocked file type from the rejection text
  2. Share the file through a link to cloud storage instead
  3. Remove or rename executables; Gmail inspects inside archives
  4. Send documents without macros where possible

What Gmail blocks

Executable and script types — .exe, .bat, .cmd, .js, .vbs, .msi and more — are blocked by extension. Archives are opened and inspected; an archive containing a blocked type is blocked. Password-protected archives that cannot be inspected are blocked. Documents with macros may be blocked when they match malware patterns.

Renaming the extension does not help; Gmail inspects content.

  • Blocked by type, including inside archives.
  • Encrypted archives are blocked because they cannot be scanned.
  • Renaming files does not bypass inspection.

Deliver the file another way

Share through Google Drive or another cloud service and send a link. For scripts and executables that must be transferred, a file-sharing service is the intended path.

For automated senders

Applications that email reports or exports should avoid blocked types and should not zip executables. Send a link to a download location instead.

Best diagnostic path

Live analysis

Mail Failure Doctor

Classify the complete rejection and preserve provider-specific diagnostic context.

Open analysis → Live analysis

Email Infrastructure Digital Twin

Map the domain’s public mail infrastructure and provider relationships before remediation.

Open analysis →

Known limits

  • Google updates the blocked-type list; the linked policy is authoritative.
  • Corporate Workspace policies can block additional types.

Common questions

The attachment is a harmless script.

Gmail cannot know that. Share it through a link.

Will a zip with a password work?

No. Encrypted archives are blocked precisely because they cannot be inspected.

Is this the same as 5.7.1?

No. 5.7.1 is a general policy rejection; 552 5.7.0 is specifically the attachment block.

Why the exact message matters

The same status family can be triggered by different conditions, and providers frequently add diagnostic text that narrows the issue. Use the complete rejection text rather than treating the numeric code as a complete diagnosis.

Provider reference

For the provider-defined meaning and current requirements, review Gmail: file types blocked in Gmail.