Reactivating a Device for DUO

If you have issues using DUO on a device (mobile phone, tablet), you might need to reactive the device with DUO.

Audience: Faculty, Staff and Students

This KB Article References: Duo Security Two-Step Login
This Information is Intended for: Faculty, Staff, Students
Last Updated: December 22, 2021
Average Rating: Not Rated
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If a DUO device you previously added isn't authenticating correctly for DUO (either online or offline), reactivate DUO Mobile for that device.  Having at least 2 devices connected to Duo or setting up Duo so that it asks you each time how you'd like to approve the log in will allow you to switch the way you authenticate if one way isn't working or available.

Why does this happen? Getting a new phone may trigger this issue even if data and apps were transferred over from the old phone.
  1. On a computer (or a browser on a device connected to the internet) go to the Duo Self-service Portal (, sign in with NetID/NetID password, and authenticate with DUO.
  2. If you get the message that Your account is not enabled for DUO, clear your browser cache and cookies and repeat from step 1 again.
  3. For the mobile device you need to reactivate duo on, click Device Options then Reactivate Duo Mobile
    Device options and reactivate Duo mobile
  4. Select the type of device (iPhone, Android, Windows Phone, Other) and click Continue
    select type of device, iPhone
  5. Click I have Duo Mobile installed
    i have duo mobile installed
  6. On the mobile device, open DUO and tap + near the top right
    duo mobile app with Stony Brook University showing and + button selected
  7. With your mobile device, scan the barcode then click Continue 
    if Continue isn't clikable, click + on your mobile device again and scan the code
    scan QR code with mobile device
  8. Your device is now reactivated for DUO mobile.

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