Frequently asked questions about Duo @ SJU

How often will I have to authenticate using Duo?

You will need to authenticate using Duo once per day (12 hour period).

If I forget my phone at home, how will I authenticate?

The Duo Login will automatically try to connect to your smartphone to authenticate, but you have the option at that screen to cancel and ask to authenticate with another method, such as a phone call to a landline.  We recommend only using that option when necessary.

Do I need to have a smartphone to use Duo?

No, we have multiple ways to authenticate with Duo. You can use a smartphone, cell phone, landline (such as your office or home phone), tablet, or hardware token. Duo works with all cell phones and landlines by supporting authentication via phone call. Just click the Call Me button on the authentication prompt (or type "phone" in the "second password" field if you don't see Duo's interactive prompt) and Duo will call your phone. Answer the call and listen to the instructions to authenticate. We recommend that users who have a smartphone choose to use them, since they are the easiest to use with Duo, and the most cost effective for the University to support.

How do I authenticate if I don't have cell service?

You can request single-use passcodes directly from the Duo Mobile app, even when your mobile device is in airplane mode or lacks cell service.

  • Simply open the app and tap the Passcode button. Depending on your device, this button may say Generate Passcode or Generate Token Code. It may also simply contain an image of a key.
  • Enter the code provided in the Passcode field of the Duo verification screen.

How do I add a new device or delete an old device?

You can manage your devices by using or following the instructions found here.

If you're replacing a device and have enabled Duo Instant Restore in the Duo app, you can follow these instructions to migrate your Duo app to your new device.

What happens if I lose my registered device?

If you lose your phone or tablet, you can and should remove it from your list of 2FA enrolled devices using the (Duo self-service portal) as soon as possible. You may also contact the Technology Service Center at 610-660-2920 to disable the Duo account connected to your missing device.


Article ID: 71139
Wed 1/30/19 11:06 AM
Tue 3/30/21 5:35 PM