Why Your Emails Keep Going to Spam: Understanding the Reasons and How to Fix Them

Emails have become an essential tool for communication in today’s business world.

Whether it’s for personal or business purposes, people rely heavily on emails to send and receive information.​

Unfortunately, despite all the effort put into crafting a well-thought-out email campaign, some emails still end up in the spam or junk folder. This can lead to missed opportunities and wasted time. But why does this happen, and how can it be prevented?

In this blog post, we’ll explore a variety of reasons (31 reasons to be exact) why your emails may end up in the junk folder and what you can do to avoid it. We’ll cover everything from email authentication failure to sending too many emails too frequently. So, let’s dive in!

What is Spam / Junk?

Spam or junk in emails refers to unsolicited or unwanted emails that are sent in bulk to a large number of recipients. These emails are typically commercial or promotional in nature and are often sent without the recipient’s consent. They can also contain malicious content such as malware or phishing links, which can harm the recipient’s device or steal their personal information.

Email providers use various techniques and filters to detect and block spam emails, in order to protect their users from potential harm and to ensure a positive email experience.

#1: Email Authentication Failure

This is the process of verifying that an email is actually sent from the sender it claims to be from. It is essential for maintaining email security and preventing email spoofing. When an email fails authentication checks, it is often flagged as spam by email service providers (ESPs).

There are several reasons why an email may fail authentication checks, including using an unverified sender domain or not properly setting up SPF, DKIM, or DMARC records. To avoid authentication failure, it is essential to set up authentication records correctly and to use a verified sender domain.

#2: Email Content Contains Malware or Viruses

Emails containing harmful content such as malware or viruses are a significant threat to email security. Therefore, most email providers have implemented filters to identify and block such emails.

If your email content contains suspicious attachments or links, it may trigger spam filters, leading to the email being flagged as junk. To avoid this, make sure to scan all attachments and links for malware and viruses before sending them.

#3: IP Address or Domain on a Blacklist

Email senders with an IP address or domain on a blacklist are more likely to be flagged as spam. ESPs use blacklists to block emails from known spammers or sources of spam. If your IP address or domain is on a blacklist, you should take steps to remove it, such as identifying and fixing any security vulnerabilities that may have caused the listing.

#4: Excessive Use of Capitalisation, Punctuation, or Symbols

Emails that use excessive capitalisation, punctuation, or symbols may be perceived as spammy and trigger filters.

This is because spammers often use such techniques to grab the recipient’s attention. To avoid this, make sure to use appropriate punctuation and capitalisation and avoid overusing symbols in your emails.

#5: Email Content Contains Offensive or Inappropriate Language

Offensive or inappropriate language can cause an email to be flagged as junk. Therefore, it is crucial to avoid using language that could be interpreted as spammy or offensive in your emails.

This includes avoiding all-caps sentences, exclamation marks, and other punctuation that may be perceived as spammy.

business people working on their spam junk emails

Why Emails Go to Spam: Additional Reasons

#6: Blacklists – If your domain or IP address is listed on major blacklists, ESPs are more likely to treat your emails as spam. 

#7: Caught in Forwarding Loops – Emails caught in forwarding loops or that are forwarded multiple times may be marked as spam.

#8: Click tracking – Including click tracking in your emails, which typically creates hyperlink masks, can trigger spam filters. 

#9: Complaints – If a significant number of recipients complain about your emails, it raises red flags for ESPs.

#10: Containing Multiple Attachments – Large emails or emails with too many attachments may be marked as junk.

#11: Content Repetition – If a large number of your emails are too similar in terms of content, it can trigger spam filters. 

#12: Domain Maturity – If your domain or IP address is relatively new, ESPs may be sceptical about the legitimacy of your emails until you establish a positive sending reputation. 

#13: Email Cadence – Sending too many emails too quickly or showing sudden spikes in send volume can trigger spam filters.

#14: High Volume of Emails – Be careful when sending a high volume of emails to a large number of recipients.

#15: History of Sending Spam Emails – Email senders with a history of sending spam emails or engaging in spam-related activities may be flagged as junk.

#16: Irrelevant or Misleading Information – Email content that contains irrelevant or misleading information can also trigger spam filters. 

#17: Misleading Subject Lines – Misleading subject lines can lead to the email being flagged as junk. It is essential to ensure that the subject line accurately represents the content of the email.

#18: New or Unknown IP Address – Use a reputable IP address and domain with a good track record to avoid triggering spam filters.

Smart Phone Using E-mail Online Messaging Concept

#19: Not Relevant to the Recipient – Emails that are not personalised or relevant to the recipient may be marked as spam.

#20: Poor Domain Reputation – Email domains with a poor reputation can be filtered as spam and can impact the deliverability of emails. 

#21: Poor Engagement – If a lower than average percentage of your recipients engage with your emails, it suggests that your emails may not be interesting or relevant to them. 

#22: Poor HTML or CSS Coding – Emails with poor coding may trigger spam filters. Be sure to test your emails thoroughly to ensure they are properly coded and free of errors.

#23: Reputation – If your domain or IP address is known for sending spammy emails, it significantly decreases your email deliverability. 

#24: Spam Keywords – Emails that contain words or phrases commonly associated with spam or phishing emails are more likely to be flagged as junk.

#25: SVG Files – These files can embed JavaScript, which presents a potential security threat. 

#26: Too Many Images – Emails that contain an abundance of images may be viewed as suspicious by spam filters. 

#27: Too Many Links – Including an excessive number of hyperlinks in your email content can make it appear spammy. 

#28: Trigger Words or Phrases – Avoid using words or phrases associated with spam to prevent your emails from being filtered.

#29: Unauthorised Sender – If your SPF, DKIM, and DMARC records are not correctly aligned, it raises suspicions about the authenticity of your emails. 

#30: Unfamiliar or Suspicious Senders – Use a recognisable and trustworthy sender name and email address to avoid being flagged as spam.

#31: Unsubscribe Links – Using unsubscribe links that lead to a blacklisted or low-reputation domain can raise concerns for ESPs. 

B2B Email Lead Generation Case Study: UK Web Design Agency


In conclusion, avoiding the spam folder is critical for the success of your email campaigns. By using verified sender domains, avoiding suspicious attachments, and following best practices for email content, you can increase the likelihood of your emails reaching their intended recipients.

Remember, email deliverability is an ongoing process, and you should regularly monitor and adjust your email campaigns to ensure optimal deliverability. To learn more about our email lead generation services or for any questions, don’t hesitate to reach out to our team.

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