If your email regularly reaches Gmail inboxes but seems to disappear when sent to Outlook, Hotmail, or Live.com addresses, the cause is often reputation-related rather than a content problem. Microsoft gives senders a direct way to check this: Smart Network Data Services, or SNDS.
What Microsoft SNDS actually shows you
SNDS is a free portal that reports how Outlook.com currently rates the reputation of the IP addresses you send email from. Where Google Postmaster Tools reports on your sending domain, SNDS focuses specifically on the IP address, which is the closest thing Microsoft offers to a reputation dashboard for senders.
The data it surfaces includes an overall reputation status, your spam complaint rate, how much mail you have sent, and how that mail was filtered on arrival.
SNDS and JMRP work together
SNDS has a companion program called the Junk Email Reporting Program (JMRP). When an Outlook user marks one of your messages as junk, JMRP sends you a report so you can identify the recipient and address the cause. SNDS tells you your reputation is slipping; JMRP helps you find out why.
Why Outlook needs a separate check from Gmail
SNDS reports specifically on Microsoft's consumer mailboxes — outlook.com, hotmail.com, live.com, and msn.com. Business filtering through Microsoft 365 runs on a related but separate system, so SNDS will not show you enterprise inbox decisions directly, though a healthy SNDS reputation is generally a good sign for how your mail performs at Microsoft 365 organizations too.
How to set up Microsoft SNDS
- Sign in. Go to the Microsoft SNDS portal and log in with any Microsoft account — it does not need to match your sending domain.
- Request access. Enter the specific IP address or IP range your email is sent from.
- Verify ownership. Microsoft sends a validation message to the abuse contact listed in the WHOIS record for that IP range, so make sure that address can actually receive mail.
- Wait for data. Reports typically begin appearing within a day or two once your IPs are verified and you have real mail volume flowing to Microsoft mailboxes.
- Enroll in JMRP. From the same portal, set a dedicated complaint address that your team actually monitors, not a shared inbox nobody checks.
How to read your SNDS data
- Reputation status is shown as a color — green for healthy, yellow for a warning, red for a serious problem. Yellow or red is your signal to investigate before filtering gets worse.
- Complaint rate and volume show how much mail each IP sent and what share of recipients complained. Watch the overall trend rather than reacting to a single day's numbers.
- Filter result shows how your traffic was actually handled, connecting a reputation drop to real filtering behavior.
Understanding the 550 5.7.515 rejection
If your mail fails Microsoft's authentication requirements for high-volume senders, you may see a bounce reading 550 5.7.515 Access denied; sending domain does not meet the required authentication level. This means your SPF, DKIM, or DMARC is not passing or not properly aligned for the domain in your From address. Check the authentication results on a message that did get delivered successfully, and fix whichever record is failing.
What to do about a yellow or red reputation
- Clean your list and remove hard bounces and unengaged contacts.
- Confirm SPF, DKIM, and DMARC all pass and are properly aligned.
- Use your JMRP feed to suppress anyone who has complained.
- Check whether your sending IP appears on a public blocklist, and follow that list's removal process if it does.
Common questions
Is SNDS the same as Google Postmaster Tools?
They serve a similar purpose but work differently. SNDS reports at the IP level for Microsoft consumer mailboxes; Google Postmaster Tools reports at the domain level for Gmail. If your recipients use both providers, it is worth setting up both.
How long after setup does SNDS start showing data?
Typically within 24 to 48 hours once your IP is verified, assuming you are sending a reasonable volume of mail to Microsoft mailboxes.
What should I do if I do not manage my own sending IP?
If your email is sent through Avalon Hosting's infrastructure, contact our support team — they can help clarify which IP range applies to your account for SNDS setup.
