Fix Microsoft 365 User Restriction After HubSpot Bulk Email
Question details
Users are being restricted in Microsoft 365 after sending bulk marketing emails through HubSpot, preventing further outbound email delivery.
- Product
- Microsoft 365 and HubSpot
- Device & OS
- not provided
- Scenario
- Sending bulk emails or marketing campaigns through HubSpot that are routed or linked via Microsoft 365 accounts.
- Observed behavior
- Microsoft 365 restricts the user accounts from sending outbound messages due to suspected spam activity, and updating anti-spam policies does not lift the restriction.
Ensure you have global administrator or Exchange administrator privileges in Microsoft 365 and access to your domain provider's DNS records before modifying authentication settings.
Configure Domain Authentication for Direct HubSpot Delivery
Apply this solution if HubSpot is configured to send emails through its own mail servers rather than routing directly through your Microsoft 365 mailboxes.
When HubSpot sends emails on behalf of your domain using its own servers, Microsoft 365 and other email providers will mark the emails as spam or restrict your domain if the sending servers are not explicitly authorized via DNS records.
Log in to your HubSpot account, click the Settings icon in the main navigation bar, and navigate to Marketing > Email > Domains.
Check the authentication status for your email sending domain. Ensure that SPF, DKIM, and DMARC are properly connected and aligned.
Log in to your domain registrar's DNS control panel. Edit your existing TXT record for SPF to include HubSpot's designated servers (e.g., adding 'include:8272546.spf05.hubspotemail.net'). Do not create a second SPF record.
Ensure your DMARC policy is set up correctly in your DNS settings. If you recently configured SPF and DKIM, keep the DMARC policy at 'p=none' until you confirm emails are authenticating successfully.
Verify SMTP Authentication and Sending Limits for Microsoft 365 Delivery
Use this method if HubSpot is connected as an email client that sends emails directly using your Microsoft 365 account credentials.
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Frequently Asked Questions
Why does Microsoft 365 restrict accounts sending bulk emails?
Microsoft 365 has strict outbound spam policies designed to protect its IP reputation. When an account sends a high volume of emails, or sends unauthenticated mail via third parties like HubSpot, Microsoft's automated systems restrict the account to prevent potential spam distribution.
How do I unblock a restricted user in Microsoft 365?
Administrators can unblock users by logging into the Microsoft 365 Defender portal. Navigate to Email & Collaboration > Review > Restricted entities, select the restricted user account, and click 'Unblock' after ensuring the account is secured and authentication issues are resolved.
Can updating my anti-spam policy fix the HubSpot sending issue?
Updating the anti-spam policy alone usually will not resolve the restriction if the root cause is incomplete domain configuration (missing SPF/DKIM) or if the user is violating hard-coded Exchange Online sending limits.
