MS Teams and Exchange Online - Student Login Issues


  • A student is having trouble logging in to Teams.
  • Student sees the message "mailbox could not be found" when accessing Outlook on the Web after signing in to Teams.


  • Oregon State University
  • Student Employee
  • Microsoft Teams, Exchange Online


Students login to Microsoft Teams with their (ONID) account.

Student employees will login to Exchange Online as (The "SE" stands for "student employee").

When logging in to Teams first and then trying to access Outlook on the Web, student employees will see an error saying "mailbox could not be found" because the ONID account is not licensed for Exchange. 

Conversely, student employees signing in to Outlook on the Web first will get an error when trying to access Teams because the Exchange account is not licensed for Teams.


To open both Teams and Outlook Web App in a web browser:

  1. Login to Teams at as
  2. Open an incognito or private browsing window and go to; login as

Alternatively, you can install the Teams app and login there, then login to Outlook on the Web via a web browser.


For assistance, contact the Service Desk.


Article ID: 104619
Tue 4/7/20 10:50 AM
Sat 8/14/21 8:13 AM