What to do when Microsoft's SNDS IP review auto-reply is received?
Matthew Whittaker
Co-founder & CTO, Suped
Published 13 Jun 2025
Updated 19 Aug 2025
7 min read
Receiving an auto-reply from Microsoft's Sender Network Data Services (SNDS) after submitting an IP review request can be a bit confusing, especially when it states, "Please do not reply to this message as it is from an unattended mailbox." It's a common scenario for many email senders, and understanding how to navigate this automated response is key to resolving any blocklist (or blacklist) issues you might be facing.
I've personally encountered this, and it often leads to questions about whether the request has been received, if further action is needed, or if the system is simply discarding your plea for help. This initial auto-reply is just the first step in Microsoft's review process, and knowing what to expect next can save you a lot of time and frustration.
Navigating the initial auto-reply
The auto-reply you receive from Microsoft's SNDS IP review system is essentially an automated acknowledgment. It confirms that your submission has been received and has been assigned a ticket number, usually found in the subject line. The line, "Errors are unlikely, however, if an error is indicated, please resubmit the specific IP or IP range," is their way of saying that the system processed your request correctly and your IP address or range is now in their queue for human review.
It's crucial to understand that this is not a human response. This particular email is generated automatically and is designed purely for notification, not for interactive communication. Therefore, replying to it, as the message explicitly states, will not yield any further response or expedite your case. Any follow-up communication or additional details should be held until a human agent contacts you, typically via a different email address or from a monitored mailbox.
Understanding the auto-reply
Confirmation: This email confirms your IP review request has entered their system.
Ticket number: Note the ticket number in the subject line, it's essential for future reference.
No reply: Do not reply to this specific automated email address.
Your immediate next step is patience. Microsoft's deliverability support team will manually review your IP address and the associated sending reputation. This process can take anywhere from a few hours to 48 hours, sometimes even longer, depending on their workload and the complexity of your case. During this period, continue to monitor your email logs and, if possible, your SNDS dashboard for any changes in your IP status. You can find more information about SNDS in their FAQ.
Following up with Microsoft
After the initial auto-reply, you should anticipate a human-generated response from Microsoft. This follow-up email will typically come from a different address and will provide a more detailed assessment of your IP's status and any actions they may have taken, or require you to take. This is the email you should reply to if you need to provide additional context, explain the issue that led to the block, or inquire about the next steps. Being prepared with information about the cause of the issue, like an error in managing bounces, can significantly help the process.
If you do not receive a human response within 48 hours, or if your sending issues persist despite SNDS showing a "normal" status, it might be necessary to resubmit your request. When doing so, reference your original ticket number to provide continuity. Sometimes, the issue might resolve itself even before you get a human response, which is a welcome surprise, but it's still good practice to confirm with Microsoft if the underlying cause was temporary.
Reactive approach (initial auto-reply)
Upon receiving the automated SNDS IP review auto-reply, the primary action is to acknowledge its receipt and verify the ticket number. This email is a system-generated notification confirming your request has been logged. Do not reply to this email, as it is from an unmonitored mailbox and your response will not be read or forwarded to a human agent. Your immediate next step is to wait for the actual human-generated follow-up.
Proactive approach (human response)
Once you receive a human-generated email from Microsoft, usually within 24-48 hours, this is your opportunity to engage. Reply to this email with any pertinent information regarding your IP address and the issue that led to the block. Provide details on steps taken to fix the problem, like rectifying bounce management errors. If no human response is received within 48 hours, consider resubmitting your request, referencing the original ticket number.
For ongoing issues with Microsoft email blocks, even when SNDS shows a normal status, it’s important to understand the nuances of their filtering. Sometimes, internal reputation metrics or recipient engagement can still lead to mail filtering. Consistent monitoring of your overall email deliverability, including bounce rates and spam complaint rates, is critical. For more on this, check out our guide on email deliverability issues.
Proactive steps to prevent blocklisting
The best way to deal with auto-replies and blocklists is to prevent them from happening in the first place. Microsoft, like other major email providers, heavily relies on sender reputation to determine inbox placement. This means ensuring your emails are consistently delivered to the inbox and not flagged as spam. Maintaining a healthy sender reputation involves several key practices.
Email authentication: Implement SPF, DKIM, and DMARC to verify your sending domain. This is non-negotiable for good deliverability. Learn more with our guide to DMARC, SPF, and DKIM.
List hygiene: Regularly clean your email lists to remove inactive or invalid addresses, reducing bounce rates and spam trap hits.
Content quality: Avoid spammy keywords, excessive links, or misleading subject lines that could trigger spam filters.
Sending volume management: Gradually increase your sending volume, especially when using a new IP, a process known as IP warming. Ignoring this can lead to Microsoft blocks during IP warming.
Additionally, actively monitoring your blocklist status and registering for feedback loops (FBLs) with major internet service providers (ISPs) can provide early warnings of reputation issues. This proactive approach minimizes the chances of your IPs ending up on a blocklist (or blacklist) and requiring manual review processes.
Best practices for email deliverability
To reduce the likelihood of encountering auto-replies from Microsoft's SNDS IP review, focus on building and maintaining a strong sender reputation. This includes authenticating your emails with SPF, DKIM, and DMARC, keeping your mailing lists clean, and sending relevant, engaging content to recipients who want to receive it. Proactive monitoring through SNDS and other postmaster tools is also essential.
The broader context of Microsoft's sender support
It's important to differentiate between the various types of automated replies and responses you might receive from Microsoft, as they each serve a different purpose. The SNDS IP review auto-reply is distinct from out-of-office replies or general bounce messages. It’s specifically tied to the delisting process for IP addresses that have been blocklisted (or blacklisted).
The key takeaway is that Microsoft's systems are designed to automate the initial intake of requests, but human intervention is still part of the process for review and resolution. The Outlook Postmaster pages confirm that automated responses are typical, and further replies to those (human) auto-responses might be needed. Persistence is often key, especially when dealing with complex IP reputation issues.
Understanding common SNDS issues can further help in diagnosing problems. If your emails are still going to spam or being blocked despite your best efforts, it's worth reviewing your email sending practices and ensuring compliance with Microsoft's latest sender requirements. Our guide on how to comply with Outlook's requirements provides a detailed overview.
Microsoft's standard auto-reply message
Please do not reply to this message as it is from an unattended mailbox. Any replies to this email will not be responded to or forwarded. This service is used for outgoing emails only and cannot respond to inquiries.
Views from the trenches
Best practices
Wait patiently for a human response after the initial auto-reply.
Monitor your SNDS dashboard for real-time changes in IP status.
Maintain meticulous email list hygiene to prevent future blocklistings.
Common pitfalls
Replying to the automated SNDS email, as it goes to an unattended mailbox.
Assuming the auto-reply means your issue is not being addressed.
Failing to track your ticket number for future correspondence.
Expert tips
If no human response arrives within 48 hours, resubmit your case referencing the original ticket number.
Always be prepared to provide context and steps taken to resolve the underlying issue.
Even if the issue resolves on its own, follow up with Microsoft if you still receive a human reply to understand the cause.
Expert view
Expert from Email Geeks says they sporadically receive these auto-responses and Microsoft usually follows up with an actual response within about 24 hours, sometimes faster.
2023-01-01 - Email Geeks
Expert view
Expert from Email Geeks says that if no follow-up is received within 48 hours, they typically resubmit the contact form.
2023-01-01 - Email Geeks
Key takeaways
Receiving Microsoft's SNDS IP review auto-reply is a standard part of their process. It confirms your request and provides a ticket number. The key is to understand its purpose: it's an acknowledgment, not an interactive communication. Your primary action after receiving it is to wait for the human-generated response, typically within 24 to 48 hours.
While you wait, focus on preventing future blocklist (or blacklist) incidents by maintaining strong email authentication, excellent list hygiene, and careful sending practices. If you don't hear back, resubmit your request, always referencing the original ticket number. Persistence and proactive reputation management are your best tools for ensuring your emails consistently reach the inbox.
Microsoft's Sender Network Data Services (SNDS) after submitting an IP review request can be a bit confusing, especially when it states, "Please do not reply to this message as it is from an unattended mailbox." It's a common scenario for many email senders, and understanding how to navigate this automated response is key to resolving any blocklist (or blacklist) issues you might be facing.
