Tenant Domain DNS no longer resolving for [thirdlevel].sharepoint.com

As of today, trying to access our tenant.sharepoint.com domain no longer resolves DNS. The same tenant.onmicrosoft.com custom domain exists in our Azure account, as per https://learn.microsoft.com/en-us/sharepoint/change-your-sharepoint-domain-name .

I can confirm that this appears to be global using DNS tools online.

Wondering if there is a setting one of our admins disabled, or a problem with MS DNS resolvers at this moment.

Any help is appreciated.

Thank you!