Strategies for repairing email domain reputation and improving deliverability with Google and Outlook
Matthew Whittaker
Co-founder & CTO, Suped
Published 15 May 2025
Updated 19 Aug 2025
9 min read
Email domain reputation is the backbone of successful email deliverability. When your domain's reputation suffers, your emails are more likely to land in spam folders or be blocked entirely by major mailbox providers like Google and Outlook. Repairing a damaged reputation requires a strategic, patient approach, focusing on rebuilding trust with these critical gatekeepers.
The challenges in restoring reputation often stem from past sending practices that led to high spam complaints, bounces, or low engagement. Overcoming these issues involves more than just a quick fix, it demands a fundamental shift in how you manage your email program. This includes everything from proper email authentication to meticulous list management.
My goal is to walk you through proven strategies to repair a low domain reputation and significantly improve your deliverability, especially when dealing with the nuanced requirements of Google and Outlook (Hotmail, Live.com, etc.). We'll cover everything from the foundational technical setups to strategic content adjustments, providing actionable steps to get your emails back into the inbox.
Understanding domain reputation and its impact
Your email domain's reputation is essentially a trust score assigned by mailbox providers like Gmail and Outlook. This score determines whether your emails reach the inbox or are diverted to the spam folder. Factors influencing this score include bounce rates, spam complaint rates, whether your domain is on a blocklist (or blacklist), and crucially, recipient engagement.
A key tool for understanding your standing with Google is Google Postmaster Tools. This platform provides valuable insights into your domain's reputation, spam rate, IP reputation, and authentication errors (SPF, DKIM, DMARC). Monitoring these metrics regularly is essential to catching issues early and preventing further damage to your reputation.
Similarly, Microsoft offers its Sender Network Data Services (SNDS) and Junk Mail Reporting Program (JMRP). While access might be more restricted if you're not directly managing your IP, your Email Service Provider (ESP) should be using these tools. If you don't own your IPs, regular communication with your ESP about your reputation metrics from Outlook's perspective is crucial.
Domain reputation and IP reputation are distinct but related concepts. Domain reputation refers to the sending domain, while IP reputation concerns the specific IP address from which your emails originate. Both are vital, but for many marketing efforts, the domain reputation often carries more weight, especially with major providers. A poor domain reputation can lead to emails being sent to spam or even blocked, regardless of a clean IP address.
Repairing reputation with Google
For Gmail, the low and slow approach is highly effective for reputation repair. This involves significantly reducing your sending volume and focusing exclusively on your most engaged subscribers. The idea is to send a small, consistent volume of highly relevant emails that generate positive engagement (opens, clicks, replies), signaling to Gmail that your emails are valued by recipients. Starting with as few as 50 highly engaged Gmail users and gradually increasing volume by about 50% each day, while monitoring your metrics, can help rebuild trust over time. You can find more details on how to recover your Gmail domain reputation in our other guides.
List hygiene is non-negotiable. Regularly purge inactive addresses, spam traps, and invalid emails to prevent high bounce rates and spam complaints, which are major reputation detractors. If someone hasn't engaged with your emails in six months or more, consider them inactive for your primary sending, and possibly sunset their address from your active list. This isn't just about deliverability, it's also about data privacy compliance in many regions.
After your reputation improves, maintaining it is key. This means continuously monitoring your engagement rates via Google Postmaster Tools and other analytics. If you have a segment of unengaged users that you believe might be valuable, try re-engaging them with a very limited, targeted campaign with compelling content and clear calls to action. If they still don't respond, it's time to let them go to protect your domain. You can learn more about strategies for improving Gmail sender reputation.
Repairing reputation with Outlook
Addressing deliverability issues with Microsoft (Outlook.com, Hotmail, Live.com) can sometimes feel less transparent than with Google. However, similar core principles apply: authentication, engagement, and content quality. Microsoft's sender support emphasizes maintaining a low complaint rate, avoiding spam traps, and adhering to their guidelines.
One effective strategy for Outlook is proactive remediation. If your emails are consistently landing in spam, gather detailed data: open rates, click-through rates, complaint rates, and evidence of your efforts to maintain a clean list and good sending practices. When contacting Microsoft support, provide a qualified ticket with all relevant data points, including screenshots and descriptions of your sending practices. This significantly increases your chances of a faster, more effective response. You can review best practices for Outlook deliverability.
Non-qualified vs. qualified tickets
Non-qualified: A basic complaint like, "My emails aren't reaching inboxes." This often leads to a generic response.
Qualified: A detailed report including specific IPs, dates deliverability dropped, comparative metrics (e.g., this IP has 2% open rate, while another has 20% on similar traffic), and proof of good practices. This helps them quickly diagnose the issue.
Be prepared to follow up diligently. Sometimes, Microsoft might agree to a remediation window (e.g., 24-48 hours). If improvements aren't seen, continue to make adjustments to your sending practices and open a new support thread if necessary. Consistency in good sending habits and persistent, data-backed communication are essential for Microsoft domains.
Foundational strategies for long-term deliverability
Email authentication is the bedrock of good deliverability and a strong reputation. SPF, DKIM, and DMARC are crucial technical records that verify your sending identity and protect your domain from spoofing and phishing. Implementing these correctly is often the first step in reputation repair and maintenance. Google's guidelines explicitly require these for bulk senders.
Engagement remains a critical signal for all mailbox providers. Consistent positive engagement, such as opens, clicks, and replies, signals that your emails are valuable. Conversely, low engagement, spam complaints, and unsubscribes negatively impact your reputation. Segmenting your audience based on engagement and sending more relevant content to active users can significantly boost your deliverability. This also means regularly removing or re-engaging inactive subscribers to avoid damaging your overall sending reputation.
Beyond technical setup, the content of your emails plays a significant role. Avoid spammy keywords, excessive images, or broken links. Ensure your emails are mobile-friendly and provide a clear, easy-to-find unsubscribe link. Personalization and relevant content can dramatically increase engagement, helping to rebuild trust with Google and Outlook. Maintaining a consistent sending volume, rather than erratic bursts, also helps maintain a stable and healthy sending reputation.
Continuous monitoring and adaptation
While repairing reputation takes time, proactive monitoring and quick action are essential. Utilize tools like Google Postmaster Tools and your ESP's analytics to keep a close eye on your sending metrics. If you notice a dip in deliverability or an increase in complaints, investigate immediately.
Getting onto a blocklist (or blacklist) can severely damage your reputation. Regularly check if your domain or sending IP has been listed on any major blocklists. If you find yourself on one, understand the reason and follow the delisting procedures. Addressing blocklist issues promptly is crucial for resuming normal email flow.
Finally, remember that reputation building is an ongoing process, not a one-time fix. Consistently applying best practices, adapting to mailbox provider guidelines, and prioritizing recipient engagement will ensure your emails continue to land in the inbox and protect your domain's sending health. You can find more information about improving a bad domain reputation in our knowledge base.
Views from the trenches
Best practices
Always prioritize sending to highly engaged subscribers, especially during reputation recovery periods to build trust.
Implement a clear sunsetting strategy for inactive subscribers to maintain a clean and responsive email list.
Routinely monitor your domain and IP reputation using tools like Google Postmaster and your ESP's analytics.
Ensure all email authentication protocols (SPF, DKIM, DMARC) are correctly configured and monitored.
Provide detailed, data-backed information when seeking remediation from mailbox providers like Microsoft.
Common pitfalls
Continuing to send to unengaged or old email addresses, which leads to low engagement and spam complaints.
Attempting to
blast
a large volume of emails after a reputation hit, worsening the problem.
Ignoring mailbox provider guidelines and authentication requirements, leading to blocks or spam folder delivery.
Expert tips
Consider a phased re-engagement strategy for inactive users if their business model allows, but be prepared to sunset them if they don't respond.
Focus on content relevance and value to drive engagement, which is the strongest signal for positive reputation.
Remember that mailbox providers sometimes have issues on their end, but always start by scrutinizing your own practices.
When reaching out for help, provide comprehensive data to demonstrate your commitment to good sending practices.
The time it takes to recover reputation varies, but consistent
Expert view
Expert from Email Geeks says the not-so-secret sauce with Gmail is focusing on very active users only. This strategy almost always leads to improvements.
2019-11-22 - Email Geeks
Expert view
Expert from Email Geeks says after reputation repair, you must learn from past mistakes and define a clear sunsetting strategy for unengaged users.
2019-11-22 - Email Geeks
Summary and final thoughts
Repairing and maintaining a strong email domain reputation with Google and Outlook is a continuous effort that blends technical correctness with smart sending practices. It requires patience, data-driven decisions, and a commitment to sending only highly relevant content to engaged audiences.
By diligently implementing email authentication, practicing rigorous list hygiene, adopting a low and slow approach during recovery, and proactively engaging with mailbox providers when necessary, you can significantly improve your deliverability and ensure your messages reach their intended recipients.
Remember, a healthy domain reputation isn't just about avoiding the spam folder, it's about building lasting trust with your subscribers and ensuring the success of your email campaigns.
Google and 
Outlook. Repairing a damaged reputation requires a strategic, patient approach, focusing on rebuilding trust with these critical gatekeepers.
