Read this closely, you will NOT use your email address to sign into Office 365 / Office 2016! Instead, Microsoft assigned each of you a special onMicrosoft.com address. For example, Gerry would sign in using gerryr@mrbk.onmicrosoft.com. However, you will still login to Outlook using your “real” email address of course.
If your regular password does not work or Microsoft makes you change it… Reset your Microsoft password