Using Duo multi-factor authentication
When you're prompted to verify your identity using Duo Mobile, you are given three methods by which you can do so: Duo Push, Call Me, and Passcode.
To have Duo to remember your authentication in this browser on this device/computer, check the Remember me for 30 days checkbox before choosing your authentication method. For more information on this feature, see How "Remember me" works in Duo multi-factor authentication.
Duo Push
This is the recommended method for verifying your identity. All it requires is an active Internet connection. Click Send Me a Push to send a prompt to your registered phone. Open Duo Mobile and tap Approve to log in.
Call me
Click Call Me to send a phone call to your registered phone. Answer the call and press any key on your phone to approve and log in. Make sure you save this phone number (847-467-9000) as one of your contacts (with a name like Northwestern Duo) so you can recognize it!

Passcode
In situations where you don't have good cell phone reception, have poor Internet access, or don't have the ability to receive an international call, your best option is to use the passcode method. This method has the added benefit of being completely free since it does not use your cellular data package.- Click Enter a Passcode to open a text box. Retrieve a passcode from your registered phone as noted in the next step, enter it in the text box, then click Log In.
- Open Duo Mobile on your registered phone and tap the down-toggle to reveal a passcode that you will enter in the text box in the step above. To generate a new passcode, tap the circular arrows.