Common Reason Why Outbound Emails Go in The Junk Folder

In the fast-paced world of business, communication is king. While new platforms and instant messaging tools constantly emerge, email remains the undeniable bedrock of professional communication.

The Business-Critical Role of Email

Think about the sheer volume and weight of communication that passes through email every day:

  • Crucial Contracts and Agreements: Legal documents, proposals, and signatures often rely on email delivery.
  • Customer Service and Support: Prompt, reliable email is essential for building trust and resolving issues.
  • Marketing and Sales: Email campaigns are a primary driver for lead nurturing and product awareness.
  • Internal Operations: Everything from project updates to HR announcements depends on smooth, consistent internal email flow.

When an important email - a sales quote, a meeting invitation, or a critical update - lands in the recipient's junk or spam folder, it's not just a minor inconvenience. It can lead to missed opportunities, client frustration, project delays, and even damaged reputations.

The goal is simple: Get your message into the primary inbox, where it belongs.

Top 5 Reasons Your Emails Land in the Junk Folder

Reason #1 - Missing or Incorrect SPF, DKIM, and DMARC Records

Missing or incorrectly set up SPF, DKIM, and DMARC is undoubtedly the top-most reason why emails go into the junk folder. Although administrators can easily resolve missing DNS entries for SPF, DKIM, and DMARC, incorrectly configured values are often overlooked and cause problems.

Here are some examples of incorrect records:

  • Multiple SPF records - SPF specifications mandate only one SPF record per domain. Often, administrators end up creating multiple TXT records starting with v=spf1 ..., which results in a PERM failure. Many spam filtering engines treat a PERM failure as junk.
    If you use third-party services to deliver your emails, add their SPF record using the include: statement.
  • Record Type - When the initial SPF specifications were created in 2006 , a new DNS record type called SPF was introduced. However, the later specifications have deprecated the SPF type in favor of the TXT type. Therefore, it is essential to remove the SPF record types for your domain and replace them with a TXT record.
  • Syntax Error - Spaces matter in SPF records. For example, the following entry will cause a PERM failure in your SPF. 
    v=spf1 ip4: 100.200.300.10/32 a mx -all
    Notice an extra space character after ip4: in the above example.
  • Incomplete DKIM Key - The public key for DKIM is larger than 256 characters. Some older DNS servers restricted the size of a TXT record to 256 characters. In such cases, you must add multiple records with subsequent entries containing the remaining characters. Simply copying and pasting the DKIM key without confirming if it was truncated results in an invalid key. Therefore, you should always confirm if your DKIM key is correctly specified by running the following command: 
    nslookup -q=txt selector._domainkey.yourdomain.com
    Replace selector and yourdomain with actual values in the example above.
Reason #2 - Misaligned DMARC

DMARC only passes if at least one of the two protocols (SPF or DKIM) passes and the domain used for that protocol aligns (matches or is a subdomain of) the "From" address visible to the user.

The sender's email address is specified in two locations:

  1. From header
  2. Return-path - or SMTP envelope

Often, administrators successfully specify the SPF and DKIM records, but fail to trace the actual path their email takes. Consider the following example:

  • You want to keep track of emails that bounce back, so you put a return path in the SMTP envelope that looks like: bounces-your-email@bounces.yourcompany.com.
  • The DKIM signature uses this same domain (bounces.yourcompany.com) for d= parameter.
  • However, the actual email address of the sender is server1@alerts.yourcompany.com.
  • In this case, the SPF and DKIM will not align because the sender's domain does not match or is a child of the domain used in the return-path.

Validation

Validate your server to confirm if your outbound emails are received correctly,
Reason #3 - IP Reputation

A quick way to confirm your IP address is not listed in an RBL server is to check the Blacklist tool on MXToolbox.

Additionally, ensure your public IP address is classified as static. Many ISPs, particularly in the United States, such as Verizon and Comcast, do not rotate dynamic IP addresses for a long time, giving the impression that they have a static IP address. Even if your IP address does not change often, if the IP is classified as dynamic, most servers on the Internet will reject incoming emails from that IP.

Reason #4 - Too Many Connections
If the receiving end detects too many incoming emails from a single IP address, they may interpret it as an attack and block your IP address. Therefore, it is essential to throttle outbound traffic when sending emails to a large number of recipients.
Reason #5 - Junk or Promotional Content

Many spam filters, such as Xeams, now use AI-powered spam filtering that can easily detect a message with junk or promotional content. Certain words and formatting styles are red flags for email filters because spammers frequently use them.

For example, using excessive capitalization (e.g., "FREE MONEY NOW!"), multiple exclamation points (!!!), or common spam trigger words ("cash," "guarantee," "winner," "urgent").

Another example is using bright red or unusual font colors, having a poor text-to-image ratio (mostly images, little text), or including broken HTML code.

The Takeaway

Getting to the inbox is about earning trust. By cleaning up your sender habits, authenticating your domain, and writing professional, clear content, you can bypass the junk folder and ensure your critical business communications are seen.