MX record intermittently loses its IP or A records is missing
November 1, 2018 | by iaur | posted as Exchange Online, Mail Flow
Scenario
- Your tenant is unable to receive emails
- Senders to your tenant is receiving NDR
- When you use MX toolbox and found out that your MX does not resolve to an IP address
Re-add the domain
This method is applicable for new tenant or tenant that don’t have any active mailboxes and mail flows yet.
https://docs.microsoft.com/en-us/microsoft-365/admin/setup/add-domain?view=o365-worldwide
Re-trigger domain’s provisioning
Access the link below to re-trigger the DNS provisioning.
https://portal-sdf.office.com/adminportal/home#/homepage
Use the workaround MX
Domain: contoso.com
Example
Affected MX: contoso-com.mail.protection.outlook.com
Workaround MX: contoso-com.mail.eo.outlook.com
Before making any changes, it’s important to use nslookup or an internet web tools against the workaround MX to verify if it resolves to an IP address.
- Run CMD as admin
- Use WhatsMyDNS tool
Steps
- If it does not resolved to an IP, proceed to step 3
- If workaround MX resolves to an IP, proceed to use it as a workaround MX for your tenant to have temporary mail flow
- Contact Microsoft 365 support to escalate it to their backend team in order to correct the issue