Your onmicrosoft.com domain can be used when the primary default domain is unavailable or experiencing problems. If you need to change the onmicrosoft.com domain, you need to add a new onmicrosoft.com domain and make it your fallback domain. In this article, you will learn how to change your onmicrosoft.com domain in Microsoft 365.
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Fallback onmicrosoft.com domain
Microsoft 365 does not automatically add a fallback onmicrosoft.com domain for every tenant. The onmicrosoft.com domain can be used when the primary default domain is unavailable or experiencing problems.
It’s essential to use the onmicrosoft.com domain as a fallback domain to ensure that emails are still delivered to the correct destination in case your default domain can’t receive emails. Another reason to have a fallback domain is if you don’t own a domain or don’t want to connect it to Microsoft 365.
To change your fallback domain name, you must first add another onmicrosoft.com domain with a new name and then set it as your fallback domain.
In our example, the fallback domain is ms365info.onmicrosoft.com.
Note: It’s only possible to change your onmicrosoft.com domain in the Microsoft 365 admin center and not in the Microsoft Entra admin center.
Step 1. Add onmicrosoft.com domain in Micosoft 365
To add an onmicrosoft.com domain in the Microsoft 365 admin center, follow these steps:
- Sign in to Microsoft 365 admin center
- Click Settings > Domains
- Click on your onmicrosoft.com domain name
- Click on the tab Overview
- Click Add onmicrosoft.com domain
- Type a new Domain name
- Click Add domain
Note: The domain you want to add can’t be removed. Make sure the spelling is correct before you add the domain, as you can only have 5 total onmicrosoft.com domains.
- Click Close
You successfully added a new domain.
Step 2. Change your onmicrosoft.com domain in Microsoft 365
When you create another onmicrosoft.com domain and make it your fallback domain, it will not change your SharePoint domain name in Microsoft 365. This can only be done with PowerShell.
Note: Before you make the new onmicrosoft.com your fallback domain, you need to change your SharePoint domain name in Microsoft 365. Otherwise, your existing SharePoint and OneDrive URLs will remain the same.
Change your onmicrosoft.com domain and make it your fallback domain with the following steps:
- Click on the new onmicrosoft domain (newms365info.onmicrosoft.com)
- Click on the tab Overview
- Click Make fallback domain
- Your fallback domain has changed to the new onmicrosoft domain (newm365info.onmicrosoft.com)
That’s it!
Read more: Add DKIM and DMARC for onmicrosoft.com domain in Microsoft 365 »
Conclusion
You learned how to change your onmicrosoft.com domain in Microsoft 365. You can’t delete the old onmicrosoft.com domain or change its name. To replace the name of your onmicrosoft.com domain, you need to add a new one and make it your fallback domain.
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