Hello Valueice,
Regarding the description, I would like to confirm if you used the correct account to log into Office 365.
Users can only use their Office 365 user ID to log into Office 365 Portal (https://portal.microsoftonline.com/). The user ID is like username@<tenant domain>.onmicrosoft.com or username@<custom domain>.
Meanwhile, make sure you log into one Office 365 service in one browser at one time. Or, you can use the InPrivate Browsing of Internet Explorer 10 by clicking Ctrl +Shift +P to try again.
If there are any other questions about this issue, you can post a new thread in the forum so that we can help you in a more efficient way.
Thanks,
Cherry Wang