How to Fix Microsoft Office 365 Emails Going to Spam

Frustrated with your Office 365 emails consistently landing in recipients’ spam folders?

Many businesses and individuals face this problem, which can significantly impact your bottom line and professional reputation.

In this article, I cover effective strategies to prevent Office 365 emails from going to spam, ensuring your messages reach their intended recipients’ inboxes.

This problem often stems from issues with email authentication, domain reputation, and content quality.

By addressing these factors, you can dramatically improve your email deliverability.

I’ll walk you through a step-by-step process to diagnose and resolve these issues, helping you maintain a healthy email sending reputation.

Check current domain authentication records

Before diving into specific solutions, it’s crucial to understand your current email authentication setup.

Our Check My Domain tool is an excellent resource for this purpose.

A web form with fields for first name, work email address, and a domain or subdomain to check, followed by a red button labeled "Check My Domain." Text below notes about updates and the use of the form for email deliverability checks.
  1. Visit the Hello Inbox homepage to use the Check My Domain tool.
  2. Enter your information in the provided fields.
  3. Click “Check My Domain.”

The tool will analyze your domain’s current authentication records, including SPF, DKIM, and DMARC.

It provides a comprehensive report highlighting any issues or missing records that could be causing your Office 365 emails to go to spam.

A screenshot of a domain check tool displaying error messages. It shows "No SSL certificate found," "SPF Record does not exist," "DKIM Record does not exist," "DMARC Record does not exist," and "MX Records do not exist." A red box below indicates the domain is not authenticated to send email.

Pay close attention to any warnings or errors in the report.

These will guide your next steps in improving your email authentication setup.

In addition to checking your authentication records, our tool will present you with a comprehensive 39-step email deliverability checklist covering infrastructure, reputation, list quality, content quality and maintenance.

Set up SPF record for Microsoft Office 365

Sender Policy Framework (SPF) is a crucial email authentication method that helps prevent spammers from sending emails using your domain.

Here’s how to set up an SPF record for Office 365:

  1. Log in to your domain registrar’s website.
  2. Navigate to your domain’s DNS settings.
  3. Create a new TXT record with the following details:
    • Host: @ (or leave blank, depending on your registrar)
    • TXT Value: v=spf1 include:spf.protection.outlook.com ~all
  4. Save the changes and allow time for propagation (usually up to 48 hours).
A form for adding a DNS record is displayed. The form includes fields for Type, Host or Name, TTL, and Content or Value. The Type is set to TXT, Host or Name to example.com, TTL to Auto, and the Content or Value reads "v=spf1 include:spf.protection.outlook.com ~all".

This SPF record tells receiving servers that Microsoft’s Office 365 servers are authorized to send emails on behalf of your domain, reducing the likelihood of your emails going to spam.

Set up DKIM records for Microsoft Office 365

DomainKeys Identified Mail (DKIM) is another crucial email authentication method that adds a digital signature to your emails.

Setting up DKIM for Office 365 involves creating CNAME records in your DNS settings.

Here’s how to do it:

  1. Log in to the Microsoft 365 Defender portal.
  2. Navigate to Email & collaboration > Policies & rules > Threat policies > Email authentication settings.
  3. Select the DKIM tab.
  4. Click on your custom domain to open the domain details flyout.
  5. Toggle the “Sign messages for this domain with DKIM signatures” switch to Enabled.
  6. A dialog box will appear with the CNAME records you need to create. It will look similar to this:
    Hostname: selector1._domainkey
    Points to address or value: selector1-yourdomain-com._domainkey.yourinitaldomain.onmicrosoft.com
    Hostname: selector2._domainkey
    Points to address or value: selector2-yourdomain-com._domainkey.yourinitaldomain.onmicrosoft.com
  7. Copy this information and go to your domain registrar’s DNS settings.
  8. Create two new CNAME records using the provided information.
  9. Save the changes and allow time for propagation.
Screenshot of the "Email authentication settings" page for DomainKeys Identified Mail (DKIM) under Policies & Rules. It shows a list of domains with names and types, including "contoso.com," and controls to refresh and add items. An info link about DKIM is provided.
Screenshot of a domain settings panel for contoso.com, showing DKIM signature options. The "Sign messages for this domain with DKIM signatures" toggle is set to Disabled. Status indicates no DKIM signatures for this domain. Last checked date: Dec 11, 2023.

After the CNAME records are detected (which can take a few minutes to several days), Microsoft 365 will automatically enable DKIM signing for your domain.

Screenshot of a settings window for contoso.com showing DKIM signature settings. Toggle switch is enabled, indicating messages for the domain will be signed with DKIM signatures. The status shows "Signing DKIM signatures for this domain" and the last checked date is Dec 11, 2023, 3:38:41 PM. Buttons at the bottom are "Rotate DKIM keys" and "Close.

This additional layer of authentication will help prevent your Office 365 emails from going to spam by verifying that the emails haven’t been tampered with during transit.

Set up DMARC record and free DMARC monitoring

Domain-based Message Authentication, Reporting, and Conformance (DMARC) is the third pillar of email authentication.

It tells receiving servers what to do with emails that fail SPF and DKIM checks.

Here’s how to set it up:

  1. Visit https://dmarc.postmarkapp.com/
  2. Enter your domain name and email address.
  3. The tool will generate a DMARC record for you. It will look similar to this:
    v=DMARC1; p=none; rua=mailto:[email protected]
  4. Add this as a TXT record in your domain’s DNS settings:
    • Host/Name: _dmarc
    • Value/Content: [The generated DMARC record]
  5. Save the changes and allow time for propagation.
A promotional graphic for a free weekly email service to help monitor and implement dmarc, detailing the benefits of dmarc, including spam reduction and authentication reports, with a signup form.
Screenshot of a webpage with a message "almost there!" followed by instructions on how to set up dmarc for email domain with a sample txt record. a "verify" button is also visible.

The free DMARC monitoring provided by Postmark will send you regular weekly reports about your domain’s email authentication status, helping you identify and address issues that might be causing your Office 365 emails to go to spam.

Add your domain to Google Postmaster Tools

Google Postmaster Tools provides valuable insights into how Gmail views emails from your domain.

To set it up:

  1. Visit Google Postmaster Tools.
  2. Log in with your personal or business Google account.
  3. Click the red circle button and enter your domain name.
  4. Verify ownership by adding a TXT record to your DNS settings.
  5. Once verified, you’ll gain access to various reports about your domain’s email performance.
A screenshot of the Google Postmaster Tools interface. Beneath a blue header reading "Postmaster Tools," a table displays two domains with their statuses listed as "Verified." A yellow arrow points to the red plus button at the bottom right, suggesting adding a new domain.
A webpage titled "Getting Started" asks, "What domain do you use to authenticate your email?" with a text box containing "example.com" as a placeholder. Below, there's a note about using the domain with SPF or DKIM for authentication. A "Next" button is at the bottom right.

This tool is invaluable for monitoring and improving your email deliverability, especially if you’re experiencing issues with Office 365 emails going to spam in Gmail accounts.

Check Domain Reputation, Spam Rate and Delivery Error reports in Google Postmaster Tools

After setting up Google Postmaster Tools, regularly check the following reports:

  1. Domain Reputation: This shows how Gmail views your domain’s sending practices. A low reputation can cause your Office 365 emails to go to spam.
  2. Spam Rate: This indicates the percentage of your emails marked as spam by recipients. High spam rates can damage your domain reputation.
  3. Delivery Errors: This report shows various types of delivery errors, which can help you identify and resolve issues causing your emails to be rejected or marked as spam.
Graph titled "Domain Reputation" shows a time range from Feb 13, 2024, to April 2, 2024, with a steady "High" reputation level. Below, a table lists domain reputation as "High" on Feb 13, Feb 24, and March 2, 2024.

Use these insights to make informed decisions about your email practices and troubleshoot issues that might be causing your Office 365 emails to go to spam.

How marketing emails can damage your domain reputation

While marketing emails are essential for many businesses, they can potentially harm your domain reputation if not managed properly.

This is especially true when using third-party email service providers (ESPs) or marketing platforms for sending these emails.

Here’s how marketing emails can damage your reputation:

  1. High volume of emails: Suddenly sending a large number of emails can trigger spam filters, especially if it’s inconsistent with your usual sending patterns.
  2. Poor list hygiene: Sending to old or unengaged contacts can lead to high bounce rates and spam complaints. This is particularly problematic when using outdated lists with a new ESP.
  3. Irrelevant content: Emails that don’t match recipients’ interests are more likely to be marked as spam, regardless of the sending platform.
  4. Lack of personalization: Generic, impersonal emails often perform poorly and may be flagged as spam.
  5. Hard bounces from third-party sends: When an ESP sends emails on your behalf to invalid addresses, the resulting hard bounces can damage your domain reputation, even though the emails didn’t originate from your Office 365 account.
  6. User-reported spam complaints: If recipients mark your marketing emails as spam, it negatively affects your sender reputation.

Remember, a damaged domain reputation can cause all your Office 365 emails to go to spam, not just marketing messages.

It’s crucial to maintain good practices across all your email sending activities, whether they originate from Office 365 or a third-party ESP.

How to reduce Spam Complaint and Hard Bounce rate to improve Domain Reputation

Reducing spam complaints and hard bounces is crucial for maintaining a good domain reputation and preventing your Office 365 emails from going to spam.

Here are some strategies:

  1. Make unsubscribing easy: Include a clear, one-click unsubscribe link in every email.
  2. Segment your list: Send targeted content to increase relevance and reduce the likelihood of spam complaints.
  3. Regularly clean your list: Remove inactive subscribers and invalid email addresses.
  4. Monitor engagement: Focus on subscribers who regularly open and interact with your emails.
  5. Use an email verification service: This can help identify and remove invalid email addresses before sending.
  6. Set expectations: Clearly communicate the type and frequency of emails subscribers will receive.

Check subject line for words or special characters that trigger spam filters

Your email subject line is the first thing spam filters evaluate.

Avoid these common triggers:

  1. ALL CAPS: “FREE OFFER TODAY!”
  2. Excessive punctuation: “Don’t Miss Out!!!”
  3. Spam trigger words: “Get Rich Quick”, “100% Free”, “Act Now”
  4. Special characters: “Sโ‚ฑโ‚ฌยขยก@L 0ffer”

Instead, use clear, concise subject lines that accurately reflect your email content.

For example:

  • “Your Monthly Newsletter from [Company Name]”
  • “Exclusive Offer for [Customer Name]”
  • “Important Update: Changes to Our Service”

Check content for words, images or links that trigger spam filters

The content of your email is equally important in avoiding spam filters.

Here are some tips:

  1. Avoid excessive use of promotional language: “Buy now!”, “Limited time offer”, “Click here”
  2. Use a balanced text-to-image ratio (more on this in the next section)
  3. Limit the number of links, especially to external domains
  4. Ensure all links are to reputable websites
  5. Use alt text for images to provide context if images are blocked
  6. Avoid attachments unless necessary, as they can trigger spam filters

Check image-to-text and link-to-text ratio

Maintaining a proper balance between images, links, and text is crucial for email deliverability.

Here are some guidelines:

  1. Image-to-text ratio: Aim for a 60:40 text-to-image ratio. Too many images can trigger spam filters.
  2. Link-to-text ratio: Keep it under 1 link per 100 words. Too many links can make your email look spammy.
  3. Use HTML text instead of text in images: This ensures your message is readable even if images are blocked.
  4. Compress images: Large file sizes can trigger spam filters and slow loading times.
  5. Use responsive design: Ensure your emails look good on both desktop and mobile devices.

Check email signature for excessive number of links or images that trigger spam filters

While email signatures are important for branding and providing contact information, they can inadvertently trigger spam filters if not designed carefully.

Here are some tips:

  1. Limit the number of links: Stick to 1-3 essential links (e.g., website, LinkedIn profile).
  2. Use text links instead of image links where possible.
  3. Avoid using large images or logos in your signature.
  4. Don’t include attachments in your signature (e.g., vCards).
  5. Use a plain, professional font rather than fancy or colorful fonts.
  6. Keep your signature concise – 4-6 lines maximum.

Perform a test and check where it goes

Before sending out a mass email, it’s crucial to test it first.

Here’s how:

  1. Set up test accounts with major email providers (Gmail, Outlook, Yahoo, etc.).
  2. Send a test email to these accounts from your Office 365 account.
  3. Check where the email lands (inbox, spam folder, or promotions tab).
  4. If it goes to spam, adjust your subject line and content.
  5. Repeat the process until your test emails consistently land in the inbox.

This testing process can help you identify and resolve issues before they affect your entire email list, reducing the chances of your Office 365 emails going to spam.

Use a warmup service to repair your domain reputation

If you’re struggling with poor domain reputation issues, a warmup and reputation repair service like Lemwarm.com can be beneficial.

Here’s how it works:

  1. Sign up for the service and connect your Office 365 account.
  2. The service gradually increases your sending volume over time.
  3. It sends emails to a network of real inboxes and generates positive engagement signals (opens, replies, moves to inbox).
  4. This activity helps to improve your sender reputation with email providers.
  5. As your reputation improves, you should see fewer instances of your Office 365 emails going to spam.
A dashboard displaying the deliverability score of 93. It shows lemwarm emails sent (1232) and emails saved from spam & categories (16). Below is a bar graph illustrating daily email landings with categories like Inbox and Spam highlighted.

While these services can be helpful, they should be used in conjunction with good email practices, not as a substitute for them.

Conclusion

Preventing Office 365 emails from going to spam requires a multi-faceted approach.

By implementing proper email authentication (SPF, DKIM, DMARC), maintaining a good domain reputation, crafting spam-filter-friendly content, and regularly monitoring your email performance, you can significantly improve your email deliverability.

Remember, email deliverability is an ongoing process.

Regularly review your practices, stay updated with email best practices, and be responsive to changes in your email performance metrics.

With persistence and attention to detail, you can ensure that your Office 365 emails consistently reach their intended recipients’ inboxes.

Frequently Asked Questions

Q: How long does it take to see improvements after implementing these changes?

A: While some changes (like SPF and DKIM setup) can have immediate effects, overall reputation improvement can take weeks or even months.

Q: Can using a third-party email marketing service help prevent my Office 365 emails from going to spam?

A: Yes, reputable email marketing services often have built-in tools and practices to improve deliverability. However, you still need to follow best practices for content and list management.

Q: What should I do if my domain reputation is already damaged?

A: Focus on cleaning your email list, improving engagement rates, and consistently following best practices. Consider using a reputation repair service if issues persist.

Q: How often should I check my email authentication and deliverability metrics?

A: It’s good practice to check these metrics at least weekly, or more frequently if you’re actively working to resolve deliverability issues.

Q: Can Office 365 emails go to spam even if I’ve set up everything correctly?

A: Yes, it’s possible. Spam filtering algorithms are complex and consider many factors. Continuous monitoring and adjustment are key to maintaining good deliverability.

By following the strategies outlined in this guide and staying informed about email best practices, you can significantly reduce the instances of your Office 365 emails going to spam and improve your overall email communication effectiveness.

Hans Desjarlais
Hans Desjarlais

Hans Desjarlais is a seasoned tech entrepreneur with over a decade of industry experience. Faced with low open rates in his previous lifestyle software business, he dived into the complexities of email deliverability, performed rigorous testing and learned to achieve remarkable results. Now, he specializes in helping companies fix their email deliverability, avoid the spam folder and boost their email ROI.

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