When you have your mobile device replaced, you need to enrol a new one on Duo.

  1. Visit the Duo Security Self-Service Portal at https://selfservice.eduhk.hk/duo_ss/.
  2. Log in with your EdUHK username, password and date of birth in the form of mm-dd. Then, click “Submit”.
  3. If you don't have your registered device (the old one), you have to generate a bypass code to log in Duo. Please see  FAQ: How can I verify my identity when I do not have my registered device with me? on how to generate the code. If you have your registered device (the old one) with you, you can click “Manage your Duo Settings” and go to the next step directly.
    Duo self services portalApply Duo Bypass code
    (Note: Please try another browser if you are not directed to the screen in step 4. It may be caused by some cache issues on your browser.)

  4. Click “Add a new device” on the left menu and choose an authentication method. If you have a bypass code generated, choose “Enter a Passcode” to verify your identity. If you have your registered device (the old one), choose “Send Me a Push” and click “Approve” on the Duo Mobile app.
    Add authentication device
  5. Choose “Mobile phone” as the primary verification device. Then click "Continue".
    Choose device type
  6. Choose Hong Kong for country code and enter your mobile phone number. Tick the check box to confirm the phone number is correct. Then click "Continue".
    Enter your phone number
  7. Choose the type of your phone (e.g. iPhone) and click "Continue".
    Choose phone type
  8. Click "I have Duo Mobile installed". (Note: Make sure you have the Duo mobile app installed on your device. If not, please install it before you proceed to next step. Please visit Install Duo Mobile app for details.)
    Prompt user to launch the Duo Mobile app
  9. When you see the following screen, open the Duo Mobile app on your mobile.
    Prompt user to scan the QR code
  10. Click “+” to add an account on your mobile device.
    Add account on Duo Mobile app
  11. Scan the QR code you get from step 9.
    Scan QR code from Duo Mobile app
  12. A six-digit passcode will be shown and your account is added successfully.
    six-digit passcode will be shown
  13. Then switch back to your computer and click “Continue”.
    QR code scanned, continue on the computer
  14. Choose "Ask me to choose an authentication method" and click "Continue to Login".
    choose an authentication method
  15. Click "Send Me a Push" to trigger the login approval process.
    Trigger login process
  16. You will then receive a notification on your mobile. Tap on the notification.
    Authenticator app icon
  17. Click “Approve” on the app as the second step of verification.
    Prompt for login in approval
  18. Your new device is added. You can choose it to be your default device. Then, click “Save”.
    Set default device


After adding a new device, you can remove any unwanted device on Duo.

  1. Click the “Device Options” button next to the device you want to remove.
    List of authentication device

  2. Click on the “trash can” button to remove the device.
    Remove authentication device

  3. Click "Remove" to confirm.
    Confirm remove device

  4. The unwanted device is removed.