Custom domain stuck in 'Deleting' state on Azure Static Web App — cannot remove or re-add

The domain entry is stuck because Azure enforces that a custom domain can only be bound to a single resource and must be fully disassociated before it can be reused. When a delete operation gets into a bad state, client-side retries (Portal, CLI, az rest) cannot clear the backend association.

From the available guidance, the only supported way to resolve a custom domain that is still logically bound to a resource but cannot be managed anymore is to have Azure Support manually unbind it. This is the same pattern used when a domain is still linked to another app or to a resource that is no longer accessible:

1. Open a support ticket in Azure Portal.
2. Clearly state that:
   • The custom domain is in Deleting for more than 24 hours on an Azure Static Web App.
   • Portal, az staticwebapp hostname delete, and direct ARM DELETE calls all report success but the domain remains.
   • The domain cannot be re-added due to the validation requirement and the existing stuck binding.
3. Be prepared to prove ownership of the domain if requested (this is standard when Azure manually releases a domain binding).
4. Ask support to manually remove the custom domain binding from the Static Web App slice/backend so the domain can be added again.

For future migrations or reassignments of the same domain between Static Web Apps:

• Ensure the domain is completely removed from the original Static Web App before adding it to another one in the same slice. Azure Static Web Apps only permit binding a unique domain to a single resource within a slice; otherwise, binding fails.
• If both apps are in the same slice and the domain must be moved without downtime, either:
  • Remove the domain from the old instance, then add it to the new one (accepting downtime), or
  • Delete and redeploy the new instance until it lands in a different slice, then bind the domain there.

If the stuck state is due to a previously deleted or inaccessible resource, the same support path applies: Azure Support can manually unbind a locked domain that is still tied to a resource that cannot be managed.

References:

• Custom domains with Azure Static Web Apps
• Troubleshoot custom domain issues in Azure App Service for web apps on Windows and Linux
• Troubleshoot domain and TLS/SSL certificate problems in Azure App Service
• Remove-AzStaticWebAppCustomDomain
• Custom domain still validating after 12 hours - Microsoft Q&A Resource:
• All cnames are on azure and ownership validation still in progress over 24 hours. There is an isssue. - Microsoft Q&A informatiksystems.com
• How do I delete a custom domain that was associated with a deleted web app? - Microsoft Q&A