Knowledge Base

Gmail Emails Go Through But Outlook Emails Go To Spam, Why?

Gmail Emails Going Through But Landing in Outlook Spam, Why?

In today's world, email communication has become an indispensable tool in both personal and professional life. However, emails not reaching recipients or ending up in the spam folder can lead to significant problems. In particular, Gmail emails ending up in the spam folder of Outlook users is a common occurrence. In this article, we will examine the possible reasons for this problem and the solutions in detail.

Why Do Gmail Emails End Up in Outlook Spam?

There can be many reasons why Gmail emails are marked as spam in Outlook. These reasons include sender-side configuration errors, recipient-side spam filters, and various factors such as the content of the email. Now let's take a closer look at these factors.

1. Authentication Deficiencies (SPF, DKIM, DMARC)

Email authentication protocols help verify that the email actually comes from the specified sender. SPF (Sender Policy Framework), DKIM (DomainKeys Identified Mail), and DMARC (Domain-based Message Authentication, Reporting & Conformance) are the most important of these protocols. If these protocols are not configured correctly, email service providers (ESPs) such as Outlook may consider the email suspicious and send it to the spam folder.

SPF (Sender Policy Framework): The SPF record contains a list of servers authorized to send emails from your domain. Outlook checks whether the incoming email comes from a server specified in the SPF record. If the email comes from a server not specified in the SPF record, it may be marked as spam.

Example SPF record:
v=spf1 include:_spf.google.com ~all
This record specifies that Google servers (Gmail) and other specified servers are authorized to send emails from this domain. The "~all" expression indicates that emails from servers not specified in the SPF record will be evaluated as "soft fail". This means that the email will not be rejected, but may be marked as spam.

DKIM (DomainKeys Identified Mail): DKIM verifies that the email has not been altered during transmission and actually comes from the specified sender by adding a digital signature to the email. This signature is created with the sender server's private key and verified by the recipient server with the sender's public key.

DKIM record example (added to DNS as a TXT record):
default._domainkey.example.com. IN TXT "v=DKIM1; k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDlkGjnJUUKvL6uyv9uEARYwSKk/jZAQZZ3Umj2dvJXT92nZ2Y4X5+Z05Q/l315+uWwQ6jJflf8O4Ywz4j7L4QIDAQAB"
This record contains the public key required to verify the DKIM signature for the "example.com" domain.

DMARC (Domain-based Message Authentication, Reporting & Conformance): DMARC brings together SPF and DKIM, giving domain owners the ability to determine how their emails should be treated based on the results of email authentication. The DMARC record can specify that emails that fail SPF and DKIM checks should be rejected, quarantined, or delivered normally. In addition, thanks to DMARC reports, domain owners can detect and correct email authentication errors.

Example DMARC record:
_dmarc.example.com. IN TXT "v=DMARC1; p=quarantine; rua=mailto:[email protected]; ruf=mailto:[email protected]; adkim=r; aspf=r;"
This record specifies that emails that fail SPF and DKIM checks should be quarantined (sent to the spam folder) and that DMARC reports should be sent to the specified email addresses.

Configuring these three protocols correctly significantly reduces the likelihood of your emails being marked as spam.

2. Email Content and Formatting

The content and formatting of the email are also examined by spam filters. The following factors may cause the email to be marked as spam:

• Excessive number of images and little text: Having too many images and little text in your email can attract the attention of spam filters. Make sure there is a balanced text and image ratio in your email content.
• Spam words and phrases: Avoid using spam words and phrases such as "Free", "discount", "click here now". These words can be triggered by spam filters.
• Malicious links: Make sure the links in your email are trustworthy. Malicious or suspicious links can be detected by spam filters.
• Incorrect HTML coding: Make sure your email's HTML coding is correct. Incorrect or complex HTML coding can cause spam filters to misinterpret the email.
• Large emails: Very large emails may be considered suspicious by spam filters. Try to keep the size of your email as small as possible.

When creating your email content, be sure to write in a way that will attract the recipient's attention and provide valuable information. By avoiding elements that may trigger spam filters, you can increase the reliability of your emails.

3. Recipient-Side Spam Filters and Settings

Recipient-side spam filters and settings can also cause your emails to end up in the spam folder. Outlook users can customize their own spam filters and settings. If a user has marked the emails you send as spam or has blocked a specific domain, your emails will automatically end up in the spam folder.

To prevent this, you can contact your recipients and ask them to mark your emails as trusted or add them to your sender list. You can also have your recipients check their spam filter settings and make sure your emails are not marked as spam.

4. IP Address and Domain Reputation Score

The reputation score of the IP address and domain from which you send emails significantly affects the deliverability of your emails. If your IP address or domain is associated with spamming or has been blacklisted, your emails may be marked as spam.

You can use various online tools to check the reputation score of your IP address and domain. If your reputation score is low, you can improve your reputation by avoiding spamming and configuring email authentication protocols correctly.

Solution Suggestions

You can apply the following solution suggestions to prevent Gmail emails from ending up in Outlook spam:

1. Configure SPF, DKIM, and DMARC records: Ensure email authentication by configuring SPF, DKIM, and DMARC records correctly for your domain.
2. Optimize email content: Avoid spam words, use a balanced text and image ratio, include trusted links, and use correct HTML coding.
3. Check IP address and domain reputation: Regularly check the reputation score of your IP address and domain, and take the necessary measures in case of low reputation.
4. Communicate with recipients: Contact your recipients and ask them to mark your emails as trusted or add them to your sender list.
5. Use Feedback Loops: Use the feedback loops offered by ESPs to track whether your emails are marked as spam and make the necessary corrections.
6. Clean your email list regularly: Reduce your bounce rate and protect your reputation by removing invalid or inactive email addresses from your list.
7. Adjust your email sending frequency: Avoid sudden and high-volume email sending. Avoid attracting the attention of spam filters by gradually increasing your email sending frequency.

Conclusion and Summary

Gmail emails ending up in Outlook spam is a common problem in email communication. The main reasons for this problem include authentication deficiencies, email content, recipient-side spam filters, and IP address/domain reputation score. By applying the solution suggestions mentioned in this article, you can significantly reduce the likelihood of your emails being marked as spam and increase the effectiveness of your email communication. Remember, to achieve success in email marketing, it is important to constantly focus on protecting and improving your reputation.