Why are my Salesforce Marketing Cloud emails going to spam after switching to a private domain and what can I do to fix it?
Michael Ko
Co-founder & CEO, Suped
Published 2 May 2025
Updated 17 Aug 2025
6 min read
Moving your email sending from a shared or generic domain to a private domain within Salesforce Marketing Cloud is often seen as a crucial step for improving deliverability. It makes sense, you gain more control and a distinct identity. However, I’ve heard from many who, like you, experience the opposite: a sudden decline in inbox placement, with emails landing in spam folders and a noticeable drop in engagement metrics like open rates and clicks, especially since the recent updates from Google and Yahoo.
This can be incredibly frustrating. You’ve invested in a private domain, following best practices, yet your emails aren't reaching their intended recipients. I want to help shed light on why this might be happening and provide actionable steps to get your Salesforce Marketing Cloud emails back into the inbox.
The strategic move to a private domain
The strategic move to a private domain is generally a positive and necessary evolution for any serious email sender. It’s about building your own dedicated sender reputation, rather than sharing it with potentially thousands of other senders on a shared domain or IP. In Salesforce Marketing Cloud, this is often facilitated through their Sender Authentication Package (SAP), which includes a private domain for email sending, links, and images.
By having a private domain, you gain direct control over your domain's DNS records, including critical authentication protocols like SPF, DKIM, and DMARC. These protocols are fundamental to proving to internet service providers (ISPs) that your emails are legitimate and haven't been spoofed or tampered with. It's a key component of brand protection and trust in the email ecosystem.
Furthermore, major mailbox providers like Google and Yahoo have tightened their sender requirements, making strong authentication and a positive domain reputation non-negotiable for high-volume senders. A private domain allows you to meet these stricter guidelines more effectively.
Importance of authentication
Properly configured SPF, DKIM, and DMARC records are vital for email deliverability with a private domain. They tell receiving servers that your emails are authentic and authorized. Misconfigurations can lead directly to spam folder placement.
Understanding these protocols is key. You can learn more about DMARC, SPF, and DKIM to ensure your setup is robust.
Navigating the post-migration landscape
While a private domain is a good step, it doesn't automatically guarantee instant inbox success. One of the most common reasons for a sudden drop in deliverability after switching is neglecting the domain warming process. Unlike shared domains which have an established reputation, a new private domain starts with no reputation, or a neutral one. Sending high volumes of emails immediately can be perceived as suspicious by ISPs, leading to spam folder placement or even a blocklist (or blacklist) designation.
Another significant pitfall is list quality. If your previous domain's reputation allowed you to get away with sending to less engaged or even invalid contacts, a new private domain might not have that luxury. These addresses can include dormant accounts, invalid emails, or even spam traps, which are highly detrimental to a new sending reputation.
Additionally, content quality might be an overlooked factor. Even with proper authentication, emails containing spammy language, broken links, or an imbalanced text-to-image ratio can trigger filters. The combination of a new domain and suboptimal content can exacerbate deliverability issues.
Expected scenario
Seamless transition: Assume immediate improvement in deliverability.
Established reputation: Leverage past sending history immediately.
Minimal effort: Focus solely on content and campaigns.
Actual scenario
Reputation reset: New domain starts with neutral or no history.
Increased scrutiny: Poor list quality or content can be amplified.
Pinpointing the root cause
If you're seeing emails land in spam, the first step is to thoroughly diagnose the issue. Don't rely solely on open rates, as new privacy features (like Apple Mail Privacy Protection) can skew these numbers. Instead, focus on click-through rates, conversions, and direct spam complaints. Salesforce Marketing Cloud's built-in reporting tools, particularly email performance by domain, can provide initial insights into where the problem lies.
Next, you need to verify your compliance with the latest sender requirements, particularly for Gmail and Yahoo. Use an external email analysis tool to check your email’s technical setup, including authentication, unsubscribe headers, and content. A reliable tool can often highlight specific technical misconfigurations or red flags that might be contributing to spam placement.
Accessing Google Postmaster Tools is critical for understanding your domain's reputation with Google. Since Salesforce Marketing Cloud often manages the DNS for your private domain, you'll need to work with them to get this set up or to gain access to the data. This platform provides invaluable insights into your sender reputation, spam rates, and authentication errors, helping you pinpoint the exact causes of deliverability issues.
One of the most critical steps to fix your deliverability is to warm up your private domain. While SFMC might handle some aspects automatically with SAP, a new domain still needs to build a positive sending history. Start by sending small volumes to your most engaged subscribers, gradually increasing over several weeks. This consistent, positive engagement signals to ISPs that you are a legitimate sender. Neglecting this step is a common reason for immediate spam issues with new domains.
Next, implement rigorous list hygiene. Regularly clean your email lists of unengaged subscribers, invalid addresses, and known spam traps. Even if your previous domain could tolerate a less-than-perfect list, your new private domain cannot. Tools like Salesforce’s List Detective help, but external validation services or re-engagement campaigns can further improve quality.
Finally, ensure your emails comply with all sender requirements. This includes having a clearly visible one-click unsubscribe link in the header (List-Unsubscribe), not just in the footer. While SFMC typically handles the technical aspect of the header unsubscribe, confirm its presence. Also, consider adopting a DMARC policy with reporting (p=none; rua=...) to gather invaluable feedback on your email authentication performance.
Implement a comprehensive domain warming schedule, even for private domains.
Regularly clean your email lists, removing unengaged subscribers and invalid addresses.
Ensure proper SPF, DKIM, and DMARC authentication for your private domain.
Monitor email performance beyond open rates, focusing on clicks and conversions.
Provide a prominent one-click unsubscribe option in your email headers.
Common pitfalls
Assuming a private domain automatically guarantees perfect deliverability.
Skipping domain warming, leading to immediate spam flagging by ISPs.
Sending to old, unengaged, or low-quality lists on a new domain.
Failing to monitor DMARC reports for authentication issues and potential abuse.
Overlooking content quality issues that can trigger spam filters.
Expert tips
Expert tip: "Prioritize collecting DMARC RUA reports. They provide actionable insights into your authentication setup."
Expert tip: "Engage with your Salesforce Marketing Cloud account manager to ensure all DNS configurations for Postmaster Tools are correctly handled."
Expert tip: "Always perform inbox testing with a new domain. This helps you understand how different mailbox providers are treating your emails."
Expert tip: "Don't dismiss declines in engagement; investigate them thoroughly to prevent a downward spiral in reputation."
Expert tip: "Ensure your Salesforce Marketing Cloud setup fully adheres to the latest Google and Yahoo bulk sender guidelines."
Expert view
Al from Email Geeks says that historically, domain warming has been seen as less critical than IP warming, but with new requirements from Google and Yahoo, skipping it entirely can lead to significant deliverability issues.
March 27, 2024 - Email Geeks
Expert view
Al from Email Geeks suggests that if it is a domain warming issue, gradually increasing send volumes over a few days for a few weeks, especially to engaged subscribers, should help things recover.
March 27, 2024 - Email Geeks
Reclaiming your inbox
Switching to a private domain in Salesforce Marketing Cloud is a sound strategic decision for long-term email marketing success. However, it's not a set-it-and-forget-it solution. The initial dip in deliverability you experienced is a common challenge, often stemming from insufficient domain warming and neglecting crucial list hygiene practices.
By actively monitoring your domain's reputation, adhering to evolving sender requirements, warming your domain diligently, and maintaining a healthy subscriber list, you can overcome these initial hurdles. Consistent effort in these areas will ensure your Salesforce Marketing Cloud emails reliably reach the inbox and contribute positively to your marketing goals.
