Why are recipients getting complaints even without DMARC implemented?
Matthew Whittaker
Co-founder & CTO, Suped
Published 9 Aug 2025
Updated 19 Aug 2025
9 min read
It can be confusing when you hear about recipients receiving complaints about emails originating from your domain, especially when you haven't implemented DMARC. Many assume DMARC is the sole gatekeeper for filtering abusive email, but that's not the full picture. Email deliverability is a complex ecosystem where various factors contribute to whether a message lands in the inbox, spam folder, or generates a complaint.
While DMARC (Domain-based Message Authentication, Reporting, and Conformance) provides a policy framework for email receivers to handle unauthenticated messages, its absence doesn't mean your domain is immune to negative feedback. Other crucial authentication protocols and general sender reputation metrics play significant roles, and their failures can lead to complaints or blocklistings, even without a DMARC policy in place.
In this article, I will explain the mechanisms that allow complaints to be generated even when DMARC isn't deployed and outline the steps you can take to mitigate these issues. Understanding these underlying factors is key to maintaining a healthy sender reputation and ensuring your legitimate emails reach their intended recipients.
Even without DMARC, mail servers still perform authentication checks using SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail). These protocols help verify the legitimacy of incoming emails. If your emails fail SPF or DKIM checks, or if they lack these records entirely, recipient mail servers might flag them as suspicious.
For example, if your domain doesn't have an SPF record, or if the sending IP address isn't listed in your SPF record, it's considered an unauthenticated message. Similarly, if your DKIM signature is missing or invalid, the email's authenticity is questioned. While DMARC provides explicit instructions on how to handle these failures (e.g., quarantine or reject), receivers often have their own internal spam filtering rules that act upon unauthenticated mail. These rules can lead to legitimate emails being marked as spam, even without DMARC. This is why many legitimate emails are marked as spam without authentication in place. You can learn more about this on Rejoiner's DMARC resource.
A common scenario is email spoofing. Spammers can forge the "From" address to make emails appear as if they come from your domain. Without DMARC, which specifically ties the visible "From" address to SPF and DKIM authentication, these spoofed emails might still pass basic SPF or DKIM checks if the actual sending server is authenticated (even if it's not yours). When recipients receive these fraudulent emails, they might hit the spam button, generating a complaint against your domain, even though you didn't send the email.
SPF Failures: If your SPF record is missing, incorrect, or doesn't include all your sending IP addresses, messages will fail SPF validation, increasing the likelihood of being marked as spam. Learn how to diagnose these issues with our guide on SPF DNS timeout failures.
DKIM Failures: An invalid or missing DKIM signature means that the email's content and headers could have been tampered with. This immediately raises suspicion with recipient servers. Check out how to fix common DKIM body hash mismatch failures.
Spoofing: Without DMARC, your domain is more vulnerable to email spoofing. Spammers can send emails appearing to be from your domain, even if they aren't using your actual sending infrastructure. These unsolicited emails can lead to complaints directed at your brand.
Common reasons for complaints
Beyond technical authentication, several other factors can cause recipients to complain about your emails, regardless of your DMARC implementation status. These include explicit spam reports, falling into spam traps, and negative IP/domain reputation.
Recipients can manually mark an email as spam or junk. This action sends a direct signal to their mailbox provider (like Google, Outlook, or Yahoo) that they consider the message unsolicited. This feedback is critical, and high complaint rates significantly damage your sender reputation, leading to future emails being routed to the spam folder or even blocked. This happens regardless of DMARC's presence. In some cases, complaints might arise from direct replies to the `From` address, especially if it's a role account, indicating a manual complaint process. This is common when email headers are forged and email clients struggle to parse them properly.
Spam traps are email addresses specifically set up by internet service providers (ISPs) and anti-spam organizations to catch spammers. Sending to a spam trap instantly damages your reputation and can lead to your IP address or domain being added to a blocklist (or blacklist). These blocklistings prevent your emails from reaching recipients, and many ISPs monitor them actively to determine whether to accept mail from your server.
Your IP and domain reputation are crucial. If your sending IP or domain has a poor reputation due to past spamming activity, high bounce rates, or low engagement, recipient servers will be highly suspicious of your emails. This can cause legitimate emails to be junked or rejected, prompting recipients to complain if they are expecting your mail. Without DMARC, it's harder for mailbox providers to definitively identify and filter malicious emails impersonating your domain, leaving the burden on their general spam filters, which might incorrectly flag legitimate messages if your overall sending behavior is problematic. You can read more on the DMARC FAQ.
Even with perfect DMARC implementation, poor email practices can lead to complaints. Factors like low engagement, irrelevant content, or a lack of proper list hygiene contribute significantly to deliverability issues.
If your recipients aren't engaging with your emails (opening, clicking), it signals to ISPs that your content might not be wanted. This negative engagement can lower your sender score, making ISPs more likely to filter your emails into spam, which in turn can lead to complaints from users who still receive them but find them annoying.
Sending content that is not relevant or expected by your audience, or emailing frequently without clear consent, also increases the likelihood of complaints. Moreover, failing to regularly clean your email list and remove inactive or invalid addresses can result in high bounce rates and spam trap hits, both of which negatively impact your reputation and increase complaint rates.
Mitigating complaints and improving deliverability
Addressing complaints without DMARC primarily involves focusing on foundational email deliverability best practices. This ensures that even in the absence of a DMARC policy, your emails are seen as legitimate and desired.
Firstly, ensure your SPF and DKIM records are correctly configured and cover all legitimate sending sources. This provides basic authentication that many mail servers still rely on. Regularly monitor your sender reputation using tools like Google Postmaster Tools and investigate any spikes in spam complaints. A high complaint rate is a clear indicator of underlying issues that need immediate attention.
To prevent spam traps and reduce bounce rates, maintain a clean email list through regular hygiene practices, removing inactive or invalid addresses. Focus on sending relevant, valuable content to engaged subscribers to minimize manual spam reports and foster positive engagement. Consider implementing DMARC, even starting with a p=none policy, to gain visibility into email authentication failures and protect your domain from spoofing. You can check your current deliverability with our Email Deliverability Tester.
Views from the trenches
Best practices
Always inspect the raw email source and full headers to understand the true path and authentication results of an email, as client-side views can be misleading.
Regularly monitor your domain's sending reputation across various mailbox providers, not just your own.
Implement a feedback loop (FBL) with major ISPs to receive direct notifications when recipients mark your emails as spam, allowing you to remove them from your list.
Ensure your email list is regularly cleaned and validated to remove invalid or disengaged addresses, reducing bounce rates and spam trap hits.
Common pitfalls
Assuming that a lack of DMARC means no complaints will be generated, overlooking manual spam reports and reputation-based filtering.
Relying solely on SPF or DKIM without DMARC, leaving your domain vulnerable to spoofing attacks that can generate complaints.
Ignoring non-technical factors like content relevance and sending frequency, which can lead to high user complaints regardless of authentication.
Failing to monitor blocklists (blacklists) and domain reputation, which can lead to widespread delivery issues and complaints.
Expert tips
Even without DMARC, explicit user complaints or manual spam reports directly impact your sender reputation, leading to blocked emails.
IP and domain reputation are paramount; unauthenticated mail or mail from suspicious IPs will likely trigger spam filters.
Spoofed emails, even without DMARC, can lead to complaints if recipients manually report them or if the `From` address is an active role account.
A comprehensive approach to email deliverability involves robust list hygiene, relevant content, and monitoring beyond just authentication.
Expert view
Expert from Email Geeks says that deciphering email headers, particularly forged ones, can be quite challenging, especially without proper tools or knowledge.
2020-01-08 - Email Geeks
Expert view
Expert from Email Geeks notes that Google's email headers can be overly complex and even internal delivery processes can introduce anomalies.
2020-01-08 - Email Geeks
Summary and recommendations
While DMARC is a powerful tool for domain protection and gaining insight into email authentication, its absence doesn't provide a shield against complaints. Mailbox providers use a holistic approach to determine email legitimacy, factoring in SPF and DKIM validation, sender reputation, content quality, and recipient engagement. Complaints can arise from spoofed emails, poor sending practices, or simply from recipients manually marking your emails as spam.
To effectively reduce complaints and improve your email deliverability, prioritize robust email authentication (SPF and DKIM), maintain a pristine sender reputation, and cultivate a highly engaged subscriber list. Implementing DMARC is still highly recommended as it provides an additional layer of protection and invaluable reporting data, empowering you to actively manage and protect your domain's email ecosystem. For more in-depth information, explore our comprehensive guide on email deliverability issues.
Google, 
Outlook, or 
Yahoo) that they consider the message unsolicited. This feedback is critical, and high complaint rates significantly damage your sender reputation, leading to future emails being routed to the spam folder or even blocked. This happens regardless of DMARC's presence. In some cases, complaints might arise from direct replies to the `From` address, especially if it's a role account, indicating a manual complaint process. This is common when email headers are forged and email clients struggle to parse them properly.
