Skip to content
MailVitals Email deliverability
Sign inEarly access
Microsoft (Outlook.com and Microsoft 365) · permanent error

550 [OU-002]: outlook.com rejection for content or reputation

Outlook.com rejected the mail for policy reasons that may relate to spam-like content or the reputation of the sending IP or domain.

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

At a glance

Code
550 [OU-002]
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 sender. The fix is on the sending side: your domain, your server or your list.

What it means

Microsoft describes OU-002 in the same words as SC-001: a policy rejection that may be related to content with spam-like characteristics or to IP or domain reputation. Microsoft does not say how the two codes differ, so treat them alike. The message is returned, not deferred. Work on the factors Outlook.com weighs, junk complaints and list accuracy above all, before asking support to look at the block.

Common causes

  • Junk complaints from Outlook.com users have hurt the IP or domain reputation.
  • The content resembles spam.
  • The list contains many invalid or unengaged addresses.

How to fix it

  1. 01Review SNDS data for the IP and act on the complaint reports JMRP sends you.
  2. 02Remove invalid and unengaged addresses from the list.
  3. 03Check the rejected content and links for spam-like patterns.
  4. 04If the block continues once those are fixed, submit the Outlook.com sender support form.

Sources

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

  1. 550 [SC-001]Outlook.com policy block for content or reputation.Outlook.com rejected the mail for policy reasons tied to spam-like content or to the reputation of the sending IP or domain.MicrosoftPermanent

550 at other providers

  1. 550Refused for a header or address problem.Yahoo or AOL refused the message for a policy reason tied to its headers, its addresses or the sending domain's DNS. Yahoo lists these as other policy errors, sent as 550 or 554.YahooPermanent
  2. 550Not an Xfinity customer.The address you sent to does not belong to an Xfinity customer. The failure is permanent, and Xfinity asks bulk mailers to treat it as an unsubscribe.ComcastPermanent
  3. 550Too many invalid recipients.Xfinity refused the whole message because too many of its recipients were invalid, so nobody received it. Clean the recipient list and send it again.ComcastPermanent
  4. 550Sender domain has no A or MX record.Xfinity refused the message because the domain you send from has neither an A record nor an MX record in DNS. Add one and send again.ComcastPermanent
  5. 550Account not available.The Xfinity account you wrote to is currently not available. Xfinity sends this as a 550, so the message has failed, though the account itself may come back.ComcastPermanent
  6. 550Permanent reject under an exceptional blocklist.GMX permanently refused mail from your system because it is on one of the blocklists GMX uses in exceptional situations. The message comes back and is not retried.GMX, WEB.DEPermanent

Further reading

All 111 Microsoft codesEvery code in the wikiPaste your own bounce

Beat · paid monitoring

A heartbeat for your email.

Beat runs every check on this site on a schedule: 41 checks, 33 blacklists and real inbox placement. The moment something breaks, it tells you what broke, why it matters, and the exact fix.

Get early access to BeatSee what Beat watches
example.comWatching
  • SPFpass
  • DKIMpass
  • DMARCp=none
  • Blacklists0 of 33

Illustrative. Your domain, every few hours.

Also from us:Pulse: your own sending infrastructureConsulting: $65/hr, no retainer