If you have activated O365 service according to activating guidelines, log in the service using username in form:

account(at)student.oulu.fi
 

• The first part of username is your University's student account, and the second part is @student.oulu.fi.
• Password is your student account's password.
• Use this username only when logging into O365 service.

Read more: Office 365 for Education, O365 email addresses