Sign up user who is created from new Azure Active Directory

I follow the tutorial from website to create new Azure AD tenant and create organizational user for this new tenant:

https://powerbi.microsoft.com/en-us/documentation/powerbi-developer-create-an-azure-active-directory-tenant/

https://powerbi.microsoft.com/en-us/documentation/powerbi-developer-sign-up-for-power-bi-service/

But when I use this new user  to sign up Power BI service, I get the error as below, how to overcome this?

My Azure AD:

The error: