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Microsoft (Outlook.com and Microsoft 365) · permanent error

550 5.6.0: moderation fails without an expiry policy tag

A message to a moderated group failed because the approval agent needs a retention tag that the organization has not created.

Microsoft
Provider
Permanent (5xx)
Class
Sources checked
By , email deliverability consultant
Author

At a glance

Code
550 5.6.0
Temporary or permanent
PermanentRefused for good: the message comes back to the sender, and resending it gets the same answer.
Who has to act
The recipient's side. Their mail admin has to change something; you can tell them.
What the server says
550 5.6.0 APPROVAL.InvalidExpiry; Cannot read expiry policy.

What it means

When a distribution group or dynamic distribution group is moderated, each message waits for a moderator's approval. The approval agent needs a retention policy tag with the IsDefaultModeratedRecipientsPolicyTag property set. If no such tag exists, senders to the group get 550 5.6.0 APPROVAL.InvalidExpiry; Cannot read expiry policy. An admin creates the tag once with Exchange Online PowerShell, and moderation then works.

Common causes

  • The group has message moderation turned on.
  • No retention policy tag in the organization has IsDefaultModeratedRecipientsPolicyTag set.

How to fix it

  1. 01Forward the report to the admin of the group's organization.
  2. 02Admins: connect to Exchange Online PowerShell and run Enable-OrganizationCustomization.
  3. 03Create the tag: New-RetentionPolicyTag -IsDefaultModeratedRecipientsPolicyTag -Name TagforModeration -AgeLimitForRetention 2.

Sources

What this page rests on, checked on 20 Oct 2026. The explanation is ours; the reply text is the server's.

  1. 554 5.6.0Attachment scan timed out under a transport rule.A Word or Excel attachment could not be scanned in time by a transport rule set to defer on failure, so the message was returned.MicrosoftPermanent
  2. 5.6.0Message content problem, unspecified.Something about the content of the message made it undeliverable, and the server did not say exactly what.StandardPermanent

5.6.0 at other providers

  1. 554 5.6.0Malformed message.Gmail refused the message because its structure breaks the Internet Message Format rules of RFC 5322, so it cannot be read reliably.GmailPermanent

All 111 Microsoft codesEvery code in the wikiPaste your own bounce

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