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.
- Microsoft
- Provider
- Permanent (5xx)
- Class
- Sources checked
- Author
At a glance
- Code
- 550 [SC-001]
- 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
SC-001 is one of the codes Outlook.com uses for a policy rejection. Microsoft gives two possible reasons: content with spam-like characteristics, or the reputation of the IP or domain. Unlike the RP codes, it is a 550, so the message is returned rather than retried. Microsoft names the junk email complaint rate as one of the main factors in a sender's reputation, so lowering complaints, cleaning lists and fixing content is what lifts it. If the block persists while you follow Outlook.com's policies, Outlook.com deliverability support takes requests through its sender support form.
Common causes
- Recent mail from the IP or domain drew junk complaints from Outlook.com users.
- The content looks like spam to Outlook.com filters.
- The IP or domain has little or poor sending history.
How to fix it
- 01Check the IP in SNDS for its reputation status and complaint data.
- 02Enroll in JMRP and remove recipients who mark your mail as junk.
- 03Review the content and links of the rejected mail for spam-like patterns.
- 04If the problem persists while you follow Outlook.com's policies, 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.
- Outlook.com Postmaster: Troubleshooting (SMTP error codes)substrate.office.com
Related codes
- 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.
- 550 [SC-004]Outlook.com block after complaints.Outlook.com placed a block on the sending IP because it received complaints about mail coming from it.
550 at other providers
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
Further reading
All 111 Microsoft codesEvery code in the wikiPaste your own bounce