Fix 'No A Record Found' for Exchange Online MX Endpoint
Question details
Users need to know how to resolve the missing A record warning for their Exchange Online MX endpoint to ensure external emails are delivered to their custom domain.
- Product
- Exchange Online
- Device & OS
- not provided
- Scenario
- Verifying and configuring custom domain DNS settings for email delivery in Microsoft 365.
- Observed behavior
- DNS tools report a 'No A Record' warning for the Microsoft 365 Exchange Online MX hostname, raising concerns that external mail servers cannot deliver messages.
Ensure you have access to your domain's DNS management portal and have Microsoft 365 global administrator privileges.
Verify and Update Your Domain's MX Record
Confirm that your MX record correctly points to the Microsoft-assigned endpoint and avoid creating manual A records.
The A record for an Exchange Online MX endpoint is entirely managed by Microsoft. You do not need to, and should not, create an A record for it in your domain's DNS zone.
Log in to the management console of your domain's DNS hosting provider and navigate to the DNS records section.
Find the MX record for your custom domain and ensure it points to the correct Microsoft 365 endpoint (typically in the format of yourdomain-com.mail.protection.outlook.com).
Delete any conflicting MX records that might interfere with mail delivery. Ensure you do not add an A record for the Exchange MX endpoint.
Open a Microsoft 365 Support Request
If email delivery continues to fail after correctly configuring your MX records, engage Microsoft Support for a backend investigation.
Try WPS Office for Seamless Document Management
While resolving your DNS and Exchange configuration issues, you can rely on WPS Office for your daily productivity needs. It is a free, lightweight, and highly compatible alternative to Microsoft Office, perfect for handling all your documents, spreadsheets, and presentations.
Frequently Asked Questions
Why do DNS tools report 'No A Record' for my Exchange MX endpoint?
The A record for the Exchange Online MX endpoint is managed internally by Microsoft's backend infrastructure. Standard DNS checking tools may report it as missing, but as long as your MX record correctly points to the mail.protection.outlook.com hostname, email delivery will work as intended.
Should I manually create an A record for Microsoft 365 email?
No, you should never create a manual A record for the Exchange Online MX endpoint in your DNS zone. Doing so can disrupt Microsoft's load balancing and cause external email delivery failures.
Do personal Outlook.com email addresses require MX records?
No, if you are using a personal Outlook.com email address rather than a custom domain connected to Microsoft 365, there are no MX records you need to configure for the personal mailbox itself.
