Troubleshooting

Step-by-step instructions are provided here.

Since Duo Mobile is tied to a specific device's hardware security module (HSM), you will need to reactivate Duo Mobile on your device by logging into the Duo Portal.

If you set up a backup device, you can use the secondary device to authenticate with.

If you generated Duo Bypass Codes, you can authenticate with bypass codes. Step-by-step instructions for generating Bypass Codes are provided.

Otherwise, if you do not have a backup device and did not generate Duo Bypass Codes, please contact Help Desk. Help Desk administrators will be able to provide a one-time use code that you can use to authenticate your identity.

If you set up a backup device, you can use the secondary device to authenticate with. It is highly recommended that you enroll multiple devices, making it less likely you are locked out of your account.

Step-by-step instructions are provided on the reactivate Duo Mobile page.

Since Duo Mobile is tied to a specific device's hardware security module (HSM), you will need to reactivate Duo Mobile on your device by logging into the Duo Portal.

Duo recommends upgrading to the most recent version of for your devices in order to ensure compatibility. More information on Duo-supported Android devices and iOS devices are provided at the respective links.

If your phone is unable to install the Duo Mobile app, there are authentication methods include using the "Call Me" or "Enter a Passcode" options.

Step-by-step guidance is provided on how to set up your device without downloading the Duo Mobile app.

There are other ways to authenticate with Duo MFA that does not require use of the Duo Mobile app.

Other alternate devices to consider would be the following:

• Landline. A telephone call to any landline phone will prompt approval or denial of the authentication attempt. A touch tone-enabled phone is eligible to be enrolled.
• Physical Token. A small lightweight keyfob that can be attached to your keychain. Pressing the button on the keyfob will generate a passcode for you to use with MFA.
• Phone. If wish to register a phone, but are unable to install the Duo Moble app or if you prefer not using the Duo Mobile, other authentication methods include using the "Call Me" or "Enter a Passcode" options. Step-by-step guidance is provided on how to set up your phone without downloading the Duo Mobile app.

Yes. Duo Security's services are used in more than 100 countries. List of countries supported by Duo.

Please note that some countries and regions outside of North America and Europe have relatively unreliable telephony infrastructure. This can lead to inconsistent phone callback and SMS authentication experiences. In these circumstances, it is recommended using alternative authentication mechanisms such as Duo Push, generating passcodes in Duo Mobile, phone callback, or hardware tokens. Another consideration to keep in mind with these countries and regions is the high cost of telephony delivery.

For more information on using international phone numbers with Duo, please visit Duo's site.

SIM cards with the same phone number.

If the Duo app is already installed on your phone and your new SIM card uses the same phone number, Duo will work as normal.

SIM cards with a different phone number.

If you have the Duo app on your phone and change to a SIM card with a different phone number:

1. Push notifications in the app — Changing SIM cards should not have any effect.
2. Text (or call) notifications – You will need to register the phone number corresponding to the new SIM card, and then select which number to use when logging in.

Yes. It is highly recommended that you enroll multiple devices, making it less likely you are locked out of your account. There are various other methods in which to receive an authentication code.

If you set up a backup device, you can use the secondary device to authenticate with.

If you have the Duo App, but no cell phone coverage, you will not be able to receive Push notifications on your cell phone. However, if you touch the SDSU logo in the Duo app, it will generate you a six-digit code users can enter for authentication.

Other options include generating a Duo Bypass Code. Step-by-step instructions of generating Bypass Codes are provided.