Error when attempting to delete a custom domain

Question

I keep getting an error when attempting to delete a custom onmicrosoft.com domain (this is not the primary or initial domain). I verified nothing is attached the to the domain (users, groups or apps) & get "All checks have passed. Proceed to delete the domain". But when I click delete I get this:

Our company just went through a name change & needing to add the new custom domain for SharePoint.

Answer 1

Hi Orvil Ownby ,

Removal of any *.onmicrosoft.com domain is not supported today. Removing this domain can also have irreversible consequences to existing Exchange and SharePoint configuration if it was ever the primary in the past. If you need to remove this domain, the workaround is to create a new tenant with the desired *.onmicrosoft.com domain and migrate the users to that new tenant.

This is also documented in Add and replace your onmicrosoft.com fallback domain in Microsoft 365:

You are limited to five onmicrosoft.com domains, and currently they cannot be deleted once they are created.

Let me know if this helps and if you have further questions. If you would like to leave feedback to change this experience and have a strong business justification, you can do so in the feedback forum. https://feedback.azure.com/

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