In Microsoft Outlook 2016 for Mac, you are repeatedly prompted for authentication while you're connected to your Office 365 account.
This issue occurs because of the presence of duplicate tokens in the keychain.
To work around this issue, delete any cached passwords for your account, and also delete any modern authentication tokens from the keychain. To do this, follow these steps.
These steps affect all Office applications that use modern authentication.
- Quit Outlook and all other Office applications.
- Start Keychain Access by using one of the following methods:
- Select the Finder application, click Utilities on the Go menu, and then double-click Keychain Access.
- In Spotlight Search, type Keychain Access, and then double-click Keychain Access in the search results.