OU Mail through Office 365 is available by going to https://outlook.office365.com.
If you are currently on the One website and wish to navigate to your OU e-mail through that site, move your cursor to the upper right hand corner and click the Application & Tools square icon.

This will open a navigation menu with various tools, select the Email option to open your Office 365 account.

From this new screen, you can click on Mail to view your OU e-mail.
