Why did my promotional emails suddenly start going to the spam folder after terminating my deliverability agency contract?
Michael Ko
Co-founder & CEO, Suped
Published 21 Jul 2025
Updated 16 Aug 2025
6 min read
It can be incredibly frustrating when promotional emails, which once consistently landed in the primary tab, suddenly divert to the spam folder, especially right after ending a contract with a deliverability agency. You might find yourself wondering what could have possibly changed so drastically in just a couple of days when you haven't altered your sending strategy or cadence.
The immediate shift from 100% primary tab placement to 100% spam folder delivery, as observed with a testing tool like Glockapps, can be alarming. While a single test email might not always be fully predictive of overall deliverability, such a stark change suggests an underlying issue that was likely being managed or mitigated by your previous agency.
Email deliverability is a complex interplay of sender reputation, technical configurations, content quality, and recipient engagement. When an agency is involved, they often handle many of these variables behind the scenes. Understanding what might have shifted is the first step in restoring your inbox placement.
Technical configuration changes
Deliverability agencies often implement and maintain crucial technical configurations that directly impact your email's ability to reach the inbox. These aren't always apparent unless you know exactly what to look for.
A common reason for a sudden drop is changes to your email authentication records, such as SPF, DKIM, and DMARC. Agencies might have configured these records to point to their own sending infrastructure, or they might have managed complex DMARC policies. Upon termination, these settings could have reverted, become misconfigured, or lost their effectiveness. This can lead to your emails failing authentication checks, which significantly impacts their deliverability and often results in them landing in the spam folder (or junk folder, as some providers call it).
For example, an agency might have added specific IP addresses or domains to your SPF record, or managed your DKIM keys. If these were removed or altered incorrectly, your emails could immediately be flagged. You can learn more about these standards in a simple guide to DMARC, SPF, and DKIM.
Another technical aspect relates to dedicated IP addresses. If your agency provided a dedicated IP that they managed, and you've reverted to a shared IP or a new, un-warmed dedicated IP without proper setup, this can severely impact your deliverability. IP warming is a process that builds trust with mailbox providers, and skipping or mishandling it can lead to immediate spam placements.
Reputation and content shifts
Email agencies often specialize in maintaining a high sender reputation by closely monitoring metrics and implementing best practices. When that oversight is removed, even a sudden drop in domain reputation is possible, even if your internal metrics initially look stable.
Agencies often manage subtle aspects of engagement and list hygiene. For instance, they might have been actively suppressing inactive subscribers, identifying and removing spam traps, or re-engaging segments to boost positive signals. If these activities ceased, your engagement metrics could quickly decline in the eyes of mailbox providers. Mailbox providers, such as Gmail, monitor how recipients interact with your emails. Low open rates, high unsubscribe rates, or an increase in spam complaints can all damage your sender reputation, making it more likely for your emails to go to the spam or junk folder. This is why it's vital to regularly clean your email list.
It's also possible that the agency had specific whitelisting agreements or relationships with certain Internet Service Providers (ISPs) or mailbox providers that expired or were revoked upon contract termination. While less common, these could have contributed to your previous primary tab placement.
Finally, the content of your emails might also play a role. Agencies sometimes optimize content to avoid spam filters or to specifically target the primary tab. If your content has become more promotional, or contains specific spam trigger words, it could easily be filtered.
Immediate steps to take
Transitioning from agency management to in-house email deliverability requires a clear understanding of your current setup and continuous monitoring. Here's how to diagnose and address the issue:
Before agency termination
DNS records: Agency likely controlled or advised on your SPF, DKIM, and DMARC records.
Sending infrastructure: Possibly used dedicated IPs or specific configurations through their own ESP.
List hygiene: Active management of inactive users, bounces, and spam complaints.
Content optimization: Content structure and wording might have been fine-tuned to avoid filters.
Monitoring: Continuous monitoring of deliverability metrics and feedback loops.
After agency termination
DNS records: Verification of SPF, DKIM, and DMARC records is critical. Any changes or omissions can cause authentication failures.
Sender reputation: Assess your email domain reputation using tools like Google Postmaster Tools. A medium or low reputation can result in spam placement.
Blacklist status: Check if your IP or domain is on any email blacklist or blocklist. A sudden change could indicate a listing, which means your emails won't reach the inbox.
Engagement monitoring: Actively monitor open rates, click rates, and spam complaints. A dip in engagement can quickly hurt deliverability.
Long-term deliverability strategy
To effectively manage your deliverability post-agency, a proactive and systematic approach is essential. This involves consistent monitoring and optimization.
Make sure your domain authentication is robust. This includes having correctly configured SPF, DKIM, and DMARC records. These are fundamental to proving your legitimacy to mailbox providers. Regularly review these settings, especially if any changes occur in your email sending infrastructure. Misconfigurations can lead to emails failing authentication and being flagged as suspicious.
Monitor your sender reputation continuously. Tools like Google Postmaster Tools provide valuable insights into how Gmail views your sending practices. Pay close attention to spam rates, IP and domain reputation, and feedback loop data. A low or medium reputation is often a precursor to deliverability issues, indicating that your emails might soon be sent to the spam or junk folder.
Implement robust list hygiene practices. Regularly remove unengaged subscribers, hard bounces, and any known spam traps. Sending to a clean and active list improves engagement metrics and signals to ISPs that your emails are valued by recipients. This proactive approach helps in avoiding getting your domain on an email blacklist or blocklist.
Moving forward to better inbox placement
While a sudden drop is concerning, it doesn't mean your deliverability is permanently ruined. Identifying the root cause is crucial, whether it's a technical misconfiguration, a shift in reputation management, or changes in content strategy.
Proactively addressing these areas and maintaining consistent monitoring will help you regain and sustain strong inbox placement for your promotional emails. Remember, email deliverability is an ongoing effort that requires continuous attention and adaptation.
Views from the trenches
Best practices
Actively manage your sender reputation through continuous monitoring of metrics.
Ensure all email authentication protocols (SPF, DKIM, DMARC) are correctly configured.
Segment your email list and send content tailored to recipient engagement.
Regularly clean your email list by removing inactive subscribers and hard bounces.
Common pitfalls
Assuming deliverability remains stable without continuous, in-house monitoring.
Neglecting to check DNS records for changes after agency contract termination.
Failing to adapt content strategy as mailbox provider algorithms evolve.
Ignoring subtle dips in engagement metrics or increases in spam complaints.
Expert tips
Use a variety of inbox placement tools, including real seed lists, for accurate insights.
Consult DMARC reports to diagnose authentication failures and identify potential issues.
Understand that deliverability is dynamic, requiring ongoing effort and adjustments.
Focus on fostering positive recipient engagement to improve sender reputation.
Expert view
Expert from Email Geeks says that landing emails in the primary tab cannot be guaranteed, as it's a combination of reputation, engagement, user behavior, and intentional user actions.
2023-02-05 - Email Geeks
Marketer view
Marketer from Email Geeks says that a single test email's bad delivery might be specific to that email and not indicative of ongoing issues, suggesting not to panic.
Gmail, monitor how recipients interact with your emails. Low open rates, high unsubscribe rates, or an increase in spam complaints can all damage your sender reputation, making it more likely for your emails to go to the spam or junk folder. This is why it's vital to regularly clean your email list.
Google Postmaster Tools provide valuable insights into how Gmail views your sending practices. Pay close attention to spam rates, IP and domain reputation, and feedback loop data. A low or medium reputation is often a precursor to deliverability issues, indicating that your emails might soon be sent to the spam or junk folder.
