@Harb369 Are you trying to enable Entra authentication with a custom domain name and roles? If you are the only user who is accessing your resource in your subscription, you should be able to access the studio with the same user account as you probably have the contributor role to your account.
Also, if key authentication is disabled in the Azure Portal, then none of the roles can list keys and speech studio authentication will fail. Please see this page for details.
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