Using Duo Mobile Multi-Factor Authentication with No Network Connection or Traveling Abroad
If there is no network connection for your mobile device (e.g. the wireless network is down or out of range), or you are out of the country, you still authenticate at a multi-factor authentication (MFA) prompt by using a passcode.
When Duo opens click Other options.
On the next screen click Duo Mobile Passcode.
Open the Duo Mobile app on your mobile device.
Tap the Show Passcodes to generate a six-digit passcode.
Enter the passcode generated by the Duo Mobile app in the Passcode field.