Q: My Outlook for PC keeps presenting the Touchstone Authentication window and will not let me into outlook.

Context

• You are on M365 (Exchange Online)
• You are running Windows 10 or newer
• You are using Outlook for your email client
• You are able to connect to email on other clients, such as mobile devices or Outlook.com

Answer

• Windows has cached outdated credential information, and Outlook attempts to use this to log in Microsoft 365 rather than the credentials acquired through touchstone.
• To clear these credentials, go to "Windows Settings" then "Accounts", then "Access Work or School". If there are any MIT related credentials listed, click "Disconnect", then "Yes". Do not disconnect any credentials related to the WIN AD domain.