Here’s a clear, step-by-step guide to unblock a blacklisted IP at Hotmail/Outlook, including how to use Microsoft’s official forms and follow-up checklist:
1. Confirm you’re blocked
- Send an email to a Hotmail/Outlook address from the suspect IP.
- If it’s blocked, you’ll receive a bounce like:
550 5.7.606 Access denied, banned sending IP [x.x.x.x]… To request removal…https://sender.office.com/This confirms Hotmail has blacklisted your IP.
(help.hostinghome.in, learn.microsoft.com, hoststud.com)
2. Investigate the cause
Check server logs around the bounce time for signs like:
- Sudden spikes in volume or bounce rates
- Spam complaints or forwarded spam
- Misconfigured DNS (SPF, DKIM, DMARC), missing PTR lookup
- Shared IP flagged by tools like Symantec/SenderScore/SNDS
These are common reasons Microsoft blocks IPs (help.hostinghome.in, glockapps.com).
Action items:
- Verify SPF, DKIM, DMARC, PTR, DNS records
- Scan for compromised accounts, malware or spam scripts
- Monitor email volume and complaints via SNDS/JMRP
3. Fix the issues first
Before requesting delisting, resolve the root cause:
- Correct DNS/Sending authentication
- Clean mailing lists (reduce bounces and complaints)
- Secure any compromised accounts or scripts
- Ensure consistent, legitimate sending patterns (hoststud.com, glockapps.com)
Submissions before fixing can be rejected or delayed .
4. Submit delisting via Microsoft portals
A. For business/Office 365 recipients
- Visit the Office 365 Anti-Spam IP Delist Portal:
https://sender.office.com - Enter the bounce-afflicted email and IP, verify the CAPTCHA
- Click Submit, check your inbox for a verification link
- Click Delist IP to begin review
- Wait up to 24 – 48 hours for removal (learn.microsoft.com, glockapps.com, sender.office.com, discourse.mailinabox.email)
B. For consumer Hotmail/Outlook addresses
If your bounce mentions error 5.7.511:
- Forward the NDR to [email protected], including the full error text and IP (learn.microsoft.com)
If bounce points to a “Hotmail Blacklist Removal Form”:
- Use Microsoft’s specific form (e.g. the one you shared) and include:
- A copy of the bounce header
- Confirmation you’ve fixed the root issue
(help.hostinghome.in, webmasters.stackexchange.com, hoststud.com)
5. Follow up proactively
- Be persistent: First request may be auto-rejected—reply again with details
- If you’re a new IP owner, provide documentation (invoice, screenshots, ISP email) to prove ownership and that you are not a spammer (discourse.mailinabox.email)
- After submission:
- Watch for Microsoft’s confirmation email
- Expect block removal in ~24–48 hours
(discourse.mailinabox.email)
6. Prevent repeat blocks
- Stay compliant with best practices:
- Maintain high sender reputation (e.g. Sender Score > 80) (glockapps.com)
- Use SNDS and JMRP to monitor activity (glockapps.com)
- Keep DNS/auth up-to-date; monitor for abuse
- Re-submit delisting promptly if IP changes or flags recur
✅ Quick Checklist
| Stage | Needed? |
|---|---|
| Bounce confirmation | ✅ |
| Diagnosis & fixes | ✅ |
| Delist form/submission | ✅ |
| Follow-up & proof | ✅ |
| Monitor reputation | ✅ |
📚 Useful Links
- Office 365 Delist Portal: https://sender.office.com (learn.microsoft.com)
- If error 5.7.511 appears, email NDR to [email protected] (learn.microsoft.com)
- Hotmail-specific removal: Use Microsoft’s form & include bounce headers and proof (help.hostinghome.in)
Final Tip
Be patient and thorough—automated systems may reject initial requests. But by fixing issues, submitting proper evidence, and following up, unblocking typically takes 1–3 business days.