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Why are my emails going to junk? Diagnostic Guide

Emails go to junk when receiving mail servers identify a lack of authentication, a poor sender reputation, or content that triggers spam filters. The most common technical cause is the absence or misconfiguration of SPF, DKIM, and DMARC records, which prevents the receiver from verifying the sender identity.

Authentication Failures

Receiving servers use SPF, DKIM, and DMARC to verify that the sending server is authorized to send mail for your domain. If SPF records are missing or DKIM signatures are invalid, the message is flagged as suspicious. DMARC provides the policy for how to handle these failures. You can use SendHQ or its free tools (https://sendhq.cc/tools) to verify if your DNS records are correctly configured according to RFC standards.

Sender Reputation and IP Health

IP and domain reputation are calculated based on historical sending patterns. High bounce rates, frequent complaints, and sending from blacklisted IPs signal low quality to ISPs. If you use a shared IP from a provider, other senders on that same IP can negatively impact your deliverability. Monitoring feedback loops via RFC 5965 helps identify why users are marking your mail as spam.

Content and Header Analysis

Spam filters analyze the ratio of text to images, the presence of trigger words, and the validity of the message structure. Non compliance with RFC 5322 regarding header formatting or improper MIME encoding as defined in RFC 2045 can trigger filters. Avoid using shortened URLs or excessive capitalization in subject lines, as these are common markers for automated spam systems.

Infrastructure and Alignment

Alignment occurs when the domain in the From header matches the domain used in SPF and DKIM. Misalignment often happens when using third party sending services. Ensure your Return-Path aligns with your visible From address to satisfy strict DMARC policies. Using a dedicated IP for high volume traffic reduces the risk of collateral reputation damage from other senders.

Questions teams ask

Does a missing SPF record cause spam placement?

Yes, many modern ISPs will automatically route mail to junk if the sending IP is not authorized in the domain SPF record.

Can DKIM fix deliverability issues?

DKIM provides a cryptographic signature that proves the email was not altered in transit, which significantly improves trust with receivers.

What is the role of DMARC in junk folder placement?

DMARC tells the receiver what to do if SPF or DKIM fails, such as rejecting the mail or sending it to the junk folder.

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