If you have used an Office 365 account on the computer before (OneDrive for Business, Skype for Business, or if you log into the computer using your Office 365 account), you may get a window prompting you to connect Outlook to Office 365. Make sure the account listed matches your email address, and click connect. If you’re trying to set up a different account, click on “Connect to a different account” on the bottom right of the window.