Hello
I bought Office 365 yesterday
I got a username and password
I logged in to Office.com and logged in, it shows i am subscribed to Office 35 E3
However, after downloading Office 365, i cannot use my username and password to register my Office 365






Please solve my problem. i dont want to pirate Office 365 like some of my colleagues.

There are many possible causes for Office 365 activation errors, for example:

Office 365 was not installed on a clean machine; an older version of Microsoft Office was installed previously.
There is an issue connecting to the Internet, the Microsoft Office 365 portal Sign in to your account or the ADFS server (sts.yourdomain.com) in your LAN or DMZ.
The user you are trying to sign-in with does not have a valid Office 365 subscription assigned.
These are but a few possible causes.
Hope you find it helpful!
Regards,
Lewis