Email deliverability. What does a Yellow status in Microsoft SNDS mean and what should I do about it?

• What does a Yellow status in Microsoft SNDS mean and what should I do about it?
• what-is-an-oob-bounce
• How can I get my emails to land in Gmail's Primary tab instead of Promotions?
• Why isn't my domain receiving emails from Email?

Microsoft's Smart Network Data Services (SNDS) uses a traffic light system:

• Green = Good reputation
• Yellow = Potential issues
• Red = Serious problems

If you're seeing Yellow status:

• Check for recent changes:

• Sudden increases in sending volume

• Higher than normal complaint rates

• Low engagement (opens/clicks)

- Take these actions:

• Maintain consistent sending volumes
• Remove unengaged subscribers
• Monitor complaint rates
• Ensure content is relevant and expected
• Verify authentication is properly configured

Yellow status often improves within a few days if you follow these practices.

Note: Want up-to-date deliverability tips? Check Email's Email Deliverability Guide in our documentation.

An "Out of Band" (OOB) bounce happens when an email is initially accepted by the receiving server but rejected later. Think of it like a letter being accepted at a post office but returned days later.

Out of Band bounces do not have a RFC standard, therefore we do not receive the same details for an OOB as an in-band bounce - we are reliant on what the mailbox provider tells us.

Common reasons for OOB bounces:

• The email address was found to be invalid
• The mailbox became full
• The message triggered spam filters after deeper analysis
• The recipient server's policies changed after initial acceptance

Gmail's tab placement is determined by their algorithms based on many factors:

• Content type and formatting
• User engagement history
• Sending patterns
• Authentication status
• Previous user interactions with your emails

While you can't directly control tab placement, these practices may help:

• Send personalized, relevant content
• Maintain consistent authentication
• Encourage recipients to move your emails to Primary
• Focus on engagement-driven content

To troubleshoot missing emails:

• Log into your Email account and check Signals:

• Look for attempted deliveries to your domain

• Check bounce reasons if deliveries are failing

• Review Message Events for specific error messages

- Common issues to check:

• DNS configuration for your domain
• Spam filter settings
• Server acceptance policies
• Full mailboxes or other technical blocks

There are several potential reasons for Microsoft delivery issues. Here's how to diagnose and fix them:

• First, check your metrics in Email Signals:

• If your bounce rate is above 2%, you'll need to clean your lists.

• If spam complaints are above 0.1%, review your content and opt-in practices.

• Look at your delayed rates to Microsoft domains.

• Check Message Events for specific Microsoft bounce codes.

• [Optional with Inbox Tracker] Review reputation using SNDS or GPT.

- Next, review any recent changes:

• Have you sent more email than usual?
• Did you change your email content?
• Are you mailing to new lists?
• Did you modify your authentication settings?

- To resolve the issue:

• Verify your authentication (SPF, DKIM, DMARC) in Email's Domains section.
• Remove inactive subscribers (no engagement for 6+ months).
• Stop sending to bounced addresses.
• Process unsubscribes immediately.
• Keep your sending volume consistent.
• Include clear unsubscribe links.
• Use clear subject lines.
• Include your physical mailing address.

Contact Email Support if:

• You've completed all these steps.
• Your metrics are within normal ranges.