Sending cold emails to multiple prospective clients from the same email address can be a powerful strategy for increasing reply rates. Studies have shown that this approach can lead to a 93% increase in responses, as recipients are more likely to view the email as coming from a legitimate source.

Indeed, the primary reason for sending cold emails from the same email address to multiple prospective clients is to increase the likelihood of your emails landing in the primary folder, rather than the spam folder. 

However, with the rise of email spam filters and increased scrutiny by email service providers (ESPs), ensuring that your emails reach your recipients' inboxes has become more challenging than ever.

Statistics also indicate that only 8.5% of outreach emails receive a response, highlighting the need for a strategic and well-executed approach.

• Are you trying to figure out why your emails are going into spam?
• Do you want to assess your email spam score?
• Not sure what email headers are and what they mean for email deliverability?
• How does copy affect your email spam score, what is the Bayesian filtering algorithm?
• How do IP addresses affect your email deliverability?
• What are spam traps, and how do you avoid them?

In this article, we'll break down every technical element for you so you can get into the email game with the full confidence of blasting through the spam filter and sit right on top of your leads primary inbox. Let’s get started.

What are the Factors that Cause Emails to Land in Spam?

Email deliverability is a critical aspect of email marketing, as it determines whether your emails reach your recipients' inboxes or get filtered into the spam folder. Understanding why emails land in spam and how to avoid it is essential for maximizing the effectiveness of your email campaigns.‍

IP Signatures and Impact

IP signatures, also known as email headers or message headers, are metadata added to an email message's SMTP trail. They include information such as the sender's IP address, the recipient's IP address, and the path the email took to reach its destination. 

These signatures play a crucial role in email deliverability, as they help email servers authenticate the sender and determine whether the email is legitimate or spam.

Consider an email header that contains the following information:

• Sender's IP address: 192.168.1.1
• Recipient's IP address: 203.0.113.1
• Path: 192.168.1.1 -> 203.0.113.1

In this example, the IP signatures indicate that the email was sent from IP address 192.168.1.1 to IP address 203.0.113.1. 

Email servers can use this information to verify that the sender is legitimate and that the email has not been spoofed or tampered with. This helps improve email deliverability by ensuring that only legitimate emails are delivered to the recipient's inbox.

How Smartlead Helps Here?

Now, Smartlead is an email sending platform, which means we access your Outlook, Gmail, or any other message outbox you connect to us, and send emails on your behalf. We are not the originators; rather, we are the sending engines that automate the process of sending messages for you. 

However, since we send emails on your behalf, there is a digital footprint, especially when using the SMTP protocol behind an SMTP network. 

Email Warm-up Policy

Smartlead operates with a policy that allows for email warm-up. It's important to note that Smartlead operates with a policy that allows for email warm-up because we are not a verified email software with respect to Gmail. 

This policy also applies to some of our competitors, while it may not be applied by others. This means that the platform gradually increases the volume of emails sent from your account to establish a positive sending reputation. This can improve the deliverability of your emails over time.

OAuth Process

When you use Smartlead or a similar platform, you need to add your Gmail account as an internal application. 

• This allows us to conduct an OAuth' process, which is more secure than using Gmail's normal 2FA or secondary application password process. 
• The 'OAuth' process helps prevent disconnects and is related to the SMTP side of things, although internally, we use Google's SMTP protocol to send messages.

IP Address Rotation‍

In contrast to the competitors in the test, when you use Smartlead, your IP address changes for every single message. 

• If an IP address gets a bad reputation for sending spam or low-quality emails, emails sent from that IP are more likely to be marked as spam or blocked. By rotating IP addresses, Smartlead avoids these reputation issues.

• Some email providers monitor the volume of emails coming from a single IP address. If they detect a sudden increase in volume, they might flag it as suspicious. 

• By rotating IP addresses distributes the sending volume across different addresses, reducing the risk of being flagged.

• ESPs often consider the diversity of IP addresses used by senders. Using a range of IP addresses can signal to ESPs that the sender is legitimate and not a spammer. By rotating IP addresses, Smartlead increases this diversity.

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RFC Internet Standardization for SMTP

RFCs (Request for Comments) are like the rulebooks of the internet, laying out the standards and protocols that make everything work smoothly.

When it comes to email, SMTP (Simple Mail Transfer Protocol) RFCs are especially important. RFCs provide detailed technical specifications and guidelines for implementing protocols like SMTP. These specifications include rules for message formatting, message transfer, error handling, and other aspects of email communication.

An example of an RFC related to SMTP is RFC 5321, which defines the current standard for the SMTP protocol. This RFC specifies the format of SMTP messages, the commands that SMTP servers should support, and how SMTP servers should handle message delivery and error conditions.

As per RFC 5321 SMTP protocol, it is very clear that when forwarding a message within or outside the internet environment, a gateway must prepend the received line. However, it must not alter that line in any way, as it is already part of the header section.

Therefore, it is part of any SMTP network to send messages where any replied messages will append to the journey of the email relay.

 The "received" line at the end of the header indicates the journey or pathway the email took to reach its current destination. 

• This process is essential for the reliability of the replay network. While it is possible to try to remove this line, it is not the correct approach. If you attempt to remove it, you may make mistakes, and some email servers may reject the email during cross-reverse IP or IP reverse checks.

•  This rejection occurs because the email appears to originate from two different points, the sender and the SMTP account, creating a significant disconnect that can increase your spam score.

In Outlook you may say “I don’t have my received header showing the IP address”. You are right, it won’t show on Outlook. This is because when using Outlook, we are using the Outlook API.

Smartlead is not directly using the SMTP engine behind Outlook to send messages. Instead, in these ESPs (Email Service Providers), we are using their APIs to send messages.

You have seen our competitors using the Gmail API, while at Smartlead, we are using the Outlook API. If you conduct a test, you will see that it is the Outlook or Microsoft 365 API in use.‍

Spam Traps Explanation and Fix

Spam traps are email addresses deliberately set up to catch and identify spam. These addresses are often generic, like sales@domain.com or info@domain.com, and are commonly found in data sources pulled from various software or networks. 

Spam traps are smartly designed to pass typical email verification checks, which usually only perform a ping check to see if the domain exists. 

However, some platforms, like Lead Magic, go further by performing a hard check to confirm the mailbox's existence in the domain and its ability to receive messages.

In more advanced cases, senders may even physically send a message to verify the mailbox's activity and validity. Failure to clean your email list of spam traps can lead to your email address being added to block lists maintained by networks like Gmail and Outlook.

These block lists are used by email service providers (ESPs) to identify bad senders who do not adhere to spam policies.

• To fix this issue, it's crucial to use a good email validation tool. Smartlead handles this by employing two separate verification tools that perform checks multiple times a day. 

• These tools verify the entire pool of email addresses, currently over 800,000, to identify any spam traps or honeypots. 

• If any suspicious activity is detected, Smartlead blocks the user account associated with the offending email address to prevent future issues.

SpamAssassin Impact

SpamAssassin plays a significant role in email deliverability and spam detection. It is a protocol and open-source software released in 2001 by Apache that many email deliverability tools rely on. 

It assigns a score to each incoming email based on factors such as the content of the email, the sender's reputation, and the email's metadata. Emails with a high spam score are more likely to be marked as spam and not delivered to the recipient's inbox.

• Whether you're using Fastmail, Gmail, a private email server, or a CPanel tool, SpamAssassin is often a part of their offering, allowing users to customize and create their own spam filters.

• Many email deliverability tools utilize SpamAssassin to emulate the spam detection experience similar to Gmail's spam policy. While Gmail's spam detection protocol remains a black box, SpamAssassin provides enough documentation for both commercial and open-source users to understand and implement it effectively.

For example, the presence of certain words or phrases commonly found in spam emails might add points to the score, while a known sender with a good reputation might reduce the score.

Suppose an email contains the word "free" multiple times in the subject line and body, which is a common spam trigger. SpamAssassin might assign a score of +5 for each occurrence of the word "free". 

• If the email also comes from a sender with a poor reputation, SpamAssassin might add another +10 to the score. 
• If the total score exceeds a certain threshold, say 15, the email is marked as spam and not delivered to the recipient's inbox.

In this example, the email's spam score would be calculated as:

5(for each occurrence of "free")+10(for sender’s poor reputation)=155( for each occurrence of "free")+10(for sender’s poor reputation)=15

This would exceed the threshold, resulting in the email being marked as spam by SpamAssassin.

• The key feature of SpamAssassin is its configurability. 

• Users can train it to identify spam based on their preferences and needs, making it a trainable model. 

• This flexibility allows users to define what constitutes spam for them, enhancing their email filtering capabilities.

Bayesian Filter for Spam Categorization

Bayesian filtering is a statistical technique used to categorize emails as either spam or non-spam based on their content. It uses a mathematical formula called Bayes' theorem to calculate the probability that an email is spam. Bayesian filters analyze the words and phrases in an email to determine its spam probability. 

Bayesian filtering is named after the statistician Rev. Thomas Bayes, who provided an equation that allows new information to update the outcome of a probability calculation. 

The rule is also known as the Bayes-Price rule after the mathematician Richard Price, who recognized the importance of the theorem, made corrections to Bayes' work, and applied the rule.

• Prior Probability: Bayesian filtering relies on prior probabilities to assess the likelihood of an email being spam. It uses past observations to determine the probability of certain words or phrases indicating spam.

• Likelihood Concept: Based on the prior probability, Bayesian filters calculate the likelihood of an email being spam given the presence of certain words or phrases. This likelihood is continually updated as new emails are processed.

The formula for Bayes' theorem is:

P(S∣W)= P(W∣S) X P(S)​ / P (W)

Where:

• P(S∣W)P(S∣W) is the probability that an email is spam given the words in the email.
• P(W∣S)P(W∣S) is the probability of observing the words in the email given that it is spam.
• P(S)P(S) is the prior probability that an email is spam.
• P(W)P(W) is the overall probability of observing the words in the email.

In spam filtering, the Bayesian theorem calculates the probability that a message is spam based on words in the email's title and body. It learns from previously identified spam and non-spam messages (often called "ham").

Unlike simple scoring filters that assign points to specific words and trigger a spam classification based on a certain score threshold, 

Bayesian filtering adapts and learns from user input. This method is more effective in capturing variations in spam tactics, such as using misspelled words or symbols to evade detection.

Spam Test Reliability

Spam tests are tools used to analyze the likelihood that an email will be marked as spam by spam filters. The reliability of a spam test depends on its ability to accurately predict how spam filters will categorize an email.

A reliable spam test can help email senders improve the deliverability of their emails by identifying and fixing potential issues before sending them.

Blacklisting on DNS Level

DNS-based blacklists (DNSBLs) are lists of IP addresses or domains that are known to send spam. Email servers use these lists to block or flag emails from blacklisted IP addresses or domains. 

Blacklisting can occur at various levels, including at the DNS level, where the domain name is blocked, or at the IP level, where the IP address is blocked. Email senders can check if their IP address or domain is blacklisted using tools like MXToolbox or Spamhaus.

Best Practices for Improve Email Deliverability to Maximize  Outreach

Sending emails that land in spam folders can be a major setback for B2B outreach efforts. To maximize the deliverability of your emails and ensure they reach your target audience, it's essential to follow best practices and implement strategies that enhance your sender reputation. Here's a how to improve email deliverability for B2B outreach:

1. Configure Your Domain with SPF, DKIM, and DMARC

Implementing SPF, DKIM, and DMARC authentication protocols is crucial for improving email deliverability and preventing spoofing:

SPF (Sender Policy Framework)

Specifies which mail servers are authorized to send emails on behalf of your domain. To configure SPF, log in to your domain registrar or DNS hosting provider's website and add a TXT record to your DNS settings with the SPF information.

By adding this SPF record to your DNS settings, you are specifying which mail servers are authorized to send emails on behalf of your domain, which helps prevent email spoofing and improves email deliverability.

DKIM (DomainKeys Identified Mail)

 Adds a unique signature to your emails that recipients can verify against a key you've shared. To configure DKIM, generate public and private DKIM keys using your email server or a third-party tool, and publish the public key in a TXT record in your DNS settings.

DMARC (Domain-based Message Authentication, Reporting, and Conformance)

Sets rules for email authentication and aligns SPF and DKIM results. To configure DMARC, add a TXT record to your DNS settings with the DMARC information, including the policy (e.g., "quarantine" or "reject") and the addresses to which reports should be sent.

Ensure that you properly configure these protocols in your domain's DNS settings to improve your email deliverability and prevent your emails from being marked as spam.

2. Warmup Your IP Address

Email warm-up is a gradual process used by senders to establish a positive sending reputation with email service providers (ESPs) and ensure better deliverability. It involves gradually increasing the volume of sent emails to signal to ESPs that you are a legitimate sender with genuine recipients.

Use tools like Smartlead to automate the warm-up process and gradually increase the volume of sent emails. This helps maintain a good sender reputation and reduces the likelihood of your emails being marked as spam.

• One of the standout features of Smartlead's warmup process is its ability to manually move emails that land in spam to the primary inbox, marking them as important. 

• This proactive approach helps boost your sender reputation and ensures that your emails get the attention they deserve.

• To further enhance email deliverability, Smartlead uses custom identifiers to protect your emails from automation parsers. This added layer of security ensures that your emails are delivered safely and reach your intended recipients.

Setting up automated warmup for your email account with Smartlead is a breeze. Once you've completed the necessary setup steps for DKIM, DMARC, SPF, and MX, follow these simple steps:

1. Sign in to the Smartlead App.

2. Navigate to the "Email Accounts" tab.

3. Select your email account to view the settings.

Smartlead supports popular email providers like Gmail, Outlook, and Zoho, so you can choose the option that corresponds to the email account you are using.

Once you've completed the necessary setup steps for DKIM, DMARC, SPF, and MX,Follow the on-screen instructions to set up automated warmup for your account.

‍3. Avoid Spam Words in Your Emails

Using spam trigger words in your B2B outreach emails can increase the chances of them being marked as spam. Avoid using words like "discount," "free," "act immediately," and others that are commonly associated with spam.

Additionally, avoid writing in all caps, using excessive punctuation, or using inflated numbers, as these can also trigger spam filters. Instead, focus on providing valuable and relevant content that resonates with your audience.

‍4. Clean Your Lists Regularly and Use Segmentation

Maintaining a clean and well-managed email list is crucial for improving deliverability. Regularly remove email addresses that result in hard bounces (emails that cannot be delivered) to keep your list clean and up-to-date.

Use segmentation to divide your email list into smaller, targeted groups based on specific criteria such as demographics, behavior, or purchase history. This allows you to send more personalized and relevant content, improving engagement and deliverability.

The Bottom Line

The future of cold email deliverability will likely see continued advancements in spam filtering algorithms and authentication technologies. Marketers will need to stay informed about these developments and adapt their email strategies accordingly.

Understanding why emails go into spam and implementing best practices to avoid them is crucial for ensuring that your emails reach your intended recipients. By following these guidelines, you can improve your cold email deliverability and maximize the effectiveness of your email marketing campaigns.

With Smartlead, you can send unlimited emails and scale your outreach efforts without worrying about Gmail's sending limits. Smartlead offers unlimited sender email accounts, allowing you to send mass emails and always land in your prospect's inbox. Additionally, Smartlead uses AI personalization to tailor your messages, increasing the effectiveness of your outreach campaigns.

FAQs

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1. How do I stop emails from landing in spam?

• Configure your domain with SPF, DKIM, and DMARC: These authentication protocols help verify your emails' authenticity and reduce the chances of them being marked as spam.
• Gradually increase your email volume: Start with a small number of emails and gradually increase to establish a positive sending reputation.
• Avoid spam trigger words: Words like "free," "discount," and "act now" can trigger spam filters. Avoid using them in your emails.
• Regularly clean your email lists: Remove inactive or invalid email addresses from your lists to improve deliverability.

2. How can I improve my email deliverability score?

To improve your email deliverability score, focus on authenticating your emails using SPF, DKIM, and DMARC protocols. Clean your email list regularly to remove inactive or invalid addresses, and segment your list for more targeted campaigns.

Avoid using spam trigger words and phrases, and pay attention to your email's text-to-image ratio. Building a good sending history and using a reputable IP address can also help improve your deliverability score.

3. How to prevent emails from going to spam in Gmail?

• Use Gmail API: Send emails using the Gmail API or similar services to improve deliverability.
• Authenticate your emails: Implement SPF, DKIM, and DMARC authentication to verify your emails' authenticity.
• Avoid spam trigger words: Refrain from using words that are likely to trigger Gmail's spam filters.

4. Why are my Outlook emails going to junk mail?

• Changes in content: Changes in the content of your emails, such as the use of new spam trigger words, can trigger Outlook's spam filters.
• IP address reputation: Changes in the reputation of the IP address you are sending emails from can affect deliverability.‍
• Authentication issues: Emails that are not properly authenticated may be flagged as spam.

5. What is email warm-up and how does Smartlead help with it?

Email warm-up is the process of gradually increasing the volume of emails sent from a new or inactive email account to establish a positive sending reputation with email service providers (ESPs).

Smartlead helps with email warm-up by automating the process and gradually increasing the volume of emails sent from your account.
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This gradual approach signals to ESPs that you are a legitimate sender with genuine recipients, improving the deliverability of your emails over time.

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