Does using Microsoft O365 for business email affect email deliverability?

Summary

The impact of using Microsoft 365 for business email on deliverability is multifaceted. Some experts argue that O365 itself doesn't inherently affect deliverability due to antitrust measures, while others suggest potential internal filtering advantages or disadvantages. A common theme is that deliverability issues often stem from improper setup (DNS, authentication), poor sending practices, and the shared IP infrastructure. Proper configuration of SPF, DKIM, and DMARC is crucial, as is proactive monitoring of domain health and sender reputation. Warming up IPs, segmenting lists, and adhering to sending limits also play a significant role.

Key findings

  • Mixed Opinions: Experts have differing views on whether O365 intrinsically impacts deliverability.
  • Setup is Paramount: Correct DNS settings, email authentication (SPF, DKIM, DMARC), and general configuration are critical for good deliverability with O365.
  • Shared IP Impact: O365's shared IP infrastructure means that your sending reputation can be influenced by other users on the same IPs.
  • Good Practices Matter: Following email marketing best practices, such as warming up IPs, segmenting lists, and personalizing messages, positively impacts deliverability.
  • Limits Exist: Exchange Online enforces sending limits to prevent spam, and exceeding those limits can hurt deliverability.

Key considerations

  • Authentication: Implement and regularly verify SPF, DKIM, and DMARC records to authenticate your domain.
  • Reputation Monitoring: Monitor your domain and IP reputation to identify and address any deliverability issues promptly.
  • IP Warming: Gradually warm up new IP addresses by increasing sending volume to build a positive sender reputation.
  • Sending Limits: Adhere to Exchange Online's sending limits to avoid deliverability problems.
  • Dedicated IPs: Consider using dedicated IPs for more control over your sending reputation, but remember the need for warming and careful management.
  • List Hygiene: Maintain clean and segmented email lists to improve engagement and reduce the risk of spam complaints.

What email marketers say
9Marketer opinions

Using Microsoft 365 for business email can affect deliverability, but not inherently. While Microsoft employs methods to maintain high deliverability, issues commonly arise from improper setup (DNS, authentication), poor sending practices (spammy content, no IP warming), and shared IP infrastructure impacting reputation. Actively managing domain reputation, sender authentication records (SPF, DKIM, DMARC), segmenting email lists, personalizing messages, and monitoring sender reputation are crucial for successful deliverability.

Key opinions

  • Setup Matters: Incorrect DNS settings and lack of proper authentication (SPF, DKIM, DMARC) are primary causes of deliverability problems.
  • Shared IPs: O365's shared IP infrastructure means your reputation is partially dependent on other users; monitoring your own reputation is vital.
  • Sending Practices: Spammy content, lack of email list segmentation, and failure to warm up IPs negatively impact deliverability.
  • Microsoft's Role: Microsoft handles the underlying infrastructure, but sender behavior strongly influences deliverability.

Key considerations

  • Authentication: Ensure SPF, DKIM, and DMARC are correctly configured to authenticate your domain and prevent spoofing.
  • Reputation Monitoring: Actively monitor your domain and IP reputation to identify and address any deliverability issues promptly.
  • IP Warming: Gradually warm up new IP addresses by increasing sending volume to establish a positive sender reputation.
  • Content Quality: Create high-quality, engaging content that avoids spam triggers to improve engagement rates and sender reputation.
  • List Segmentation: Segment your email lists to send targeted and personalized messages, improving engagement and reducing spam complaints.
Marketer view

Email marketer from Digital Marketing Forum mentions that smaller businesses might experience deliverability challenges with O365 if they're not actively managing their domain reputation and sender authentication records.

August 2024 - Digital Marketing Forum
Marketer view

Email marketer from Microsoft Community responds that Microsoft 365 uses various methods to ensure high deliverability rates, including maintaining a good IP reputation and adhering to email authentication standards (SPF, DKIM, DMARC).

September 2022 - Microsoft Community
Marketer view

Email marketer from Small Business Forum explains using O365 helps him with deliverability because Microsoft handles the infrastructure and reputation, but he needs to make sure his emails aren't spammy.

April 2024 - Small Business Forum
Marketer view

Email marketer from Reddit shares that while O365 itself is reputable, deliverability issues often arise from improper setup, poor sending practices, or being flagged as spam by recipients.

December 2022 - Reddit
Marketer view

Email marketer from Email Marketing Agency Website shares that segmenting your email lists and personalizing your messages can improve engagement rates, which positively impacts your sender reputation and deliverability when using O365.

June 2021 - Email Marketing Agency Website
Marketer view

Email marketer from MSP Forum mentions warming up the O365 IP address gradually with increasing volume is important for new domains to establish a good sender reputation.

February 2025 - MSP Forum
Marketer view

Email marketer from Email Vendor Blog discusses that O365's shared IP infrastructure means your deliverability can be affected by other users on the same IPs. Monitoring your sender reputation is crucial.

October 2024 - Email Vendor Blog
Marketer view

Email marketer from Tech Support Blog shares common O365 deliverability issues such as incorrect DNS settings, not warming up the IP address, and spam filter triggers.

January 2023 - Tech Support Blog
Marketer view

Email marketer from Email Deliverability Consulting Website answers correctly configuring SPF, DKIM and DMARC is crucial to ensuring good deliverability from O365.

July 2024 - Email Deliverability Consulting Website

What the experts say
5Expert opinions

Opinions on whether Microsoft O365 impacts deliverability are mixed. Some experts suggest O365 itself doesn't inherently affect deliverability due to anti-trust concerns, while others believe internal filtering and knowledge of sender information might provide subtle advantages or disadvantages. A consensus exists on the importance of proper configuration (SPF, DKIM, DMARC) and dedicated IPs for improved deliverability and sender reputation management within O365.

Key opinions

  • Neutral Impact?: Some believe O365 doesn't measurably affect deliverability due to anti-trust requirements enforcing equal treatment.
  • Internal Filtering: O365's internal filtering and knowledge of sender data *could* influence deliverability, leading to subtle advantages or disadvantages, although the extent is debated.
  • Authentication is Key: Correct SPF, DKIM, and DMARC setup is crucial for proving sender authenticity and improving deliverability within O365.
  • Dedicated IPs: Using dedicated IPs with O365 can enhance deliverability by isolating your sending reputation, but requires proactive management and warming.

Key considerations

  • Configuration: Ensure SPF, DKIM, and DMARC records are properly configured for your domain in O365.
  • Internal vs. External: Consider potential internal filtering differences when sending mail within the O365 ecosystem.
  • IP Strategy: Evaluate whether dedicated IPs are necessary for your sending volume and reputation management needs in O365.
  • Reputation Management: Monitor your sender reputation and follow best practices for email sending to maintain good deliverability within the shared O365 environment.
  • IP Warming: If using a dedicated IP, slowly warm up the IP to establish a reputable sending history.
Expert view

Expert from Email Geeks shares that using O365 doesn't affect deliverability in any measurable way, referencing anti-trust issues.

December 2023 - Email Geeks
Expert view

Expert from Spam Resource explains using dedicated IP addresses with O365 can improve deliverability by isolating your sending reputation from other users, but requires proper IP warming and management.

November 2021 - Spam Resource
Expert view

Expert from Word to the Wise explains that correct setup of SPF, DKIM and DMARC records is critical for deliverability when using O365, particularly to prove sender authenticity to receiving mail servers.

September 2021 - Word to the Wise
Expert view

Expert from Email Geeks explains that O365's knowledge of the source and mail volume could influence deliverability.

January 2023 - Email Geeks
Expert view

Expert from Email Geeks wonders about unintentional advantages of sending from O365 to O365, citing cold lead complaints and internal filtering differences.

February 2022 - Email Geeks

What the documentation says
3Technical articles

Microsoft's documentation emphasizes that Exchange Online implements sending limits to control spam and safeguard system health, which can indirectly impact deliverability if these limits are surpassed. Both Microsoft and MXToolbox documentation stresses the significance of utilizing SPF, DKIM, and DMARC for email authentication to enhance deliverability in Exchange Online, along with proactively monitoring domain health to identify and address deliverability concerns.

Key findings

  • Sending Limits: Exchange Online enforces sending limits to prevent spam, potentially impacting deliverability if exceeded.
  • Authentication is Crucial: SPF, DKIM, and DMARC are vital for authenticating your domain and improving email deliverability within Exchange Online.
  • Proactive Monitoring: Regularly monitor domain health for blacklist status and proper configuration of SPF, DKIM, and DMARC to mitigate deliverability problems when using O365.

Key considerations

  • Stay Within Limits: Be aware of and adhere to Exchange Online's sending limits to avoid deliverability issues.
  • Implement Authentication: Configure SPF, DKIM, and DMARC records correctly to authenticate your domain and improve deliverability.
  • Monitor Domain Health: Use tools like MXToolbox to proactively monitor your domain's health and quickly address any deliverability problems.
Technical article

Documentation from MXToolbox explains proactive monitoring of your domain's health, including checking blacklist status, SPF, DKIM, and DMARC records, can help mitigate deliverability issues when using O365.

January 2024 - MXToolbox
Technical article

Documentation from Microsoft explains Exchange Online enforces sending limits to prevent spam and maintain system health, which can impact deliverability if exceeded.

April 2023 - Microsoft
Technical article

Documentation from Microsoft explains the importance of using SPF, DKIM, and DMARC to authenticate your domain and improve deliverability when sending emails through Exchange Online.

October 2024 - Microsoft