my outgoing emails keep getting blocked as spam

Hi Rio Whyte

I understand how frustrating it is when your emails are being rejected like this. Have you already tried the Q&A Assist suggestions? In addition, could you confirm:

• Does the issue happen with all recipients or only specific ones?
• Does a plain text test email go through successfully?
• Are you sending to many recipients at once, or sending similar emails repeatedly?

In the meantime, please test from another platform, try sending the same email using Outlook web version via https://outlook.live.com (If you are using your phone browser, please change your browser to desktop view). Also, sometimes Outlook.com may temporarily limit sending if unusual activity is detected.

Please try:

• Sign in at Outlook web
• Look for any prompts like “Verify your account” or security checks
• Complete any verification if shown

Looking forward to your reply so I can guide you further. Thank you for your understanding.

The error 550 5.7.520 Message blocked because it contains content identified as spam. AS(4810) means the Outlook.com service is classifying the message (or the sending account/server) as spam and is blocking delivery.

Use these steps:

1. Check message content and attachments
   • Remove any suspicious wording, large numbers of links, or “spammy” phrases.
   • Temporarily remove attachments (especially multiple PDFs, images, or executables) and resend a simple text-only message to test.
   • If text-only messages send successfully, gradually re-add content/attachments to identify what triggers the block.
2. Verify the recipient side isn’t blocking you as spam/blacklisted
   • If the non‑delivery report mentions being “blocked” or “listed in” a blacklist (Spamhaus, Spamcop, etc.), the recipient’s server believes the sending server/account is a spam source.
   • In that case, the recipient (or their admin) should contact their email provider’s support or postmaster to request unblocking of the sending address or domain.
3. If sending from Outlook.com or a Microsoft consumer address (@outlook.com, @hotmail.com, @live.com, @msn.com)
   • Ensure the account is not sending bulk or promotional mail that could be treated as spam.
   • If messages with normal content and no attachments are still blocked, use the Outlook.com sender support channel to have deliverability reviewed. For IT/admin scenarios, use the troubleshooting form referenced in Sender Support to contact Microsoft about deliverability issues to Outlook.com recipients.
4. If sending from a non‑Microsoft mail server to Outlook.com recipients
   • Review the sending IP and domain reputation (blacklists, spam complaints, volume spikes).
   • Make sure the server and accounts are not compromised or used for spam or “namespace mining.” If any IP is blocked for namespace mining, clean up compromised systems and stop any address‑harvesting behavior, then request remediation via the Outlook.com sender support troubleshooting form.
5. If this started suddenly and you changed nothing
   • There may be a temporary reputation or filtering issue. After confirming that content is legitimate and systems are not compromised, contact Outlook.com sender support using the troubleshooting link in the Sender Support article so Microsoft can review the block.

If the account is business‑critical and all content is legitimate, the key actions are: simplify/test content, ensure no compromise or abusive behavior, then escalate via the Outlook.com sender support troubleshooting form for a reputation review.

References:

• Sent email in Outlook.com comes back "delivery failed"
• Sender Support in Outlook.com