1. Quit Outlook if it's running.
  2. Open Terminal using one of the following methods:
    • With Finder as the selected application, on the Go menu click Utilities, and then double-click Terminal.
    • In Spotlight Search, type Terminal, and then double-click Terminal from the search results.
  3. Enter the following command in the Terminal window, and then press Enter.

    defaults write com.microsoft.Outlook TrustO365AutodiscoverRedirect -bool true 
  4. On the Terminal menu, click Quit Terminal.