Duo: How to Authenticate When Your Phone Has No Internet Access

If you wish to authenticate your Microsoft Outlook login via Duo, but don't have Internet access on your phone or other Duo verification device, choose the Other Options link on the initial “Check for a Duo Push”authentication window (see first image). Then, on the following screen (second image), choose the Duo Mobile passcode option and enter the Passcode number found on the main screen of your Duo app. In order to see the Passcode number on your Duo app (fourth image), click the Show link (third image).