My email appears as spam and is being rejected.

If email sent from Outlook.com is being rejected as spam, there are two main areas to check: delivery errors and sender reputation.

1. Check the exact error message
   • If a Non-Delivery Report (NDR) or “delivery failed” message is returned, review the error text.
   • If it mentions terms like "blocked", "listed in", or references to sites like "spamcop," "dynablock," "blackhole," or "spamhaus", the recipient’s server is intentionally blocking the message as suspected spam.
   • In that case, the recipient’s email provider must unblock the account or domain. Contact their support and provide the error details so they can remove the block.
2. Improve spam reputation when sending to Outlook.com/Hotmail users If messages to Outlook.com/Hotmail recipients are failing because the sending IP or account has poor spam reputation, use these steps:
   1. If anti-virus software is installed, look for Internet Email Auto Protect or Internet Email Protection. If enabled, temporarily disable this feature and send a test message.
   2. Ensure the “From” name is clearly identifiable. Add a proper display name to outgoing email so the “send as” identity looks legitimate.
   3. Send an email to the same account, open it, and reply to it. This can help establish normal, interactive usage rather than one‑way bulk sending.
   4. Add trusted senders to Contacts so their replies and interactions are treated as legitimate traffic.
3. If acting as an IT admin or sending from own mail server to Outlook.com
   • Ensure sending practices comply with Microsoft’s policies and guidelines.
   • If messages still have delivery problems to Outlook.com addresses (@outlook.com, @hotmail.com, @live.com, @msn.com) and the issue is not covered by the standard FAQs, use the Outlook.com sender support troubleshooting form (linked in the documentation) to contact support and request help with deliverability.
4. When messages come back “delivery failed” from Outlook.com
   • For transient errors like “Can’t connect to remote server/message expired” or “Connection timed out”, wait and resend; these often resolve automatically.
   • For group delivery failures, verify all recipient addresses in the error report and remove invalid ones.
   • For blacklist/"blocked" errors, only the recipient’s provider can remove the block, so their support must be contacted.

If the error is specifically "550 5.1.8 Access denied, bad outbound sender" in a Microsoft 365/Exchange Online environment, the account may have exceeded sending limits or been flagged for outbound spam. In that case, the admin must secure the account and unblock it on the Restricted entities page in the Microsoft 365 Defender portal.

References:

• Sender Support in Outlook.com
• Sent email in Outlook.com comes back "delivery failed"
• NDR error code "550 5.1.8 Access denied, bad outbound sender"
• I receive a 550, 553, or relay-prohibited error when sending email messages