Microsoft is transitioning all CRM organizations from the "standalone" CRM Online platform (which uses Windows Live IDs for authentication) to the Office 365 platform. The transition is free, and takes a couple of hours. You can read more about it here: blogs.technet.com/.../how-the-transition-will-affect-users-of-crm-online.aspx
If you contact Support, they can help you schedule a convenient transition time.