Duo Mobile is a two-factor authentication app that generates time-based passcodes and lets you approve or deny login requests directly from your phone. To use Duo Mobile, you install the app on your iPhone or Android device, link it to your account, and then either tap a push notification to approve a login or type a six-digit passcode into the login prompt.
What is Duo Mobile and how to use it
Duo Mobile adds a second layer of security to your online accounts by requiring something you have (your phone) in addition to something you know (your password). The app generates time-based one-time (TOTP) passcodes that refresh every 30 seconds, and it can also receive Duo Push authentication requests that you approve or deny with a single tap. Beyond Duo-protected accounts, the app supports third-party TOTP accounts, making it a versatile authenticator for any service that offers standard two-factor authentication.
How to install Duo Mobile on iPhone and Android
To install Duo Mobile, open the App Store on an iPhone or iPad, or open Google Play on an Android phone. Duo Mobile supports Apple Watch in addition to iPhone and iPad. Search for "Duo Mobile" and tap the download or install button. Duo Mobile version 4 requires iOS 17 on Apple devices and Android 12 on Android devices; the app has been removed from stores for devices running iOS 16 and earlier or Android 11 and earlier. Duo Mobile version 4 on Apple devices requires iOS 17 and was removed from the App Store for iOS 16 and earlier. Duo Mobile version 4 on Android requires Android 12 and was removed from the Play Store for Android 11 and earlier. After installation, open the app and grant any permissions it asks for, such as camera access for scanning QR codes and notification access for receiving login requests.
How to set up Duo Mobile and link your account
After opening Duo Mobile, you will see options to add an account. The most common method is to scan a QR code provided by the service you are securing. Tap "Scan QR Code" and align your device's camera with the QR code on the screen. If no QR code is available, tap "Add Account" and manually enter the account provider name, your username, and the shared secret key provided by the service. If your organization uses device management or activation links, you may be able to log in with a passcode generated by Duo Mobile and request a new activation link sent to your phone. During setup, confirm phone number with 'Yes, it's correct' or go back with 'No, I need to change it'. During passwordless setup, tap 'Open Duo Mobile' to open the app for the device check.
If you need to set up Duo Mobile on a new phone, simply install the app on the new device and repeat the linking process using the same activation method your organization provides. To set up a Duo Mobile account, follow the same steps: download the app, scan the QR code or enter the key, and confirm your phone number if prompted. Note that the process for how to set up Microsoft authenticator on new phone is different, Duo Mobile requires its own activation steps and does not use Microsoft account recovery methods.
How to generate passcodes in Duo Mobile
- Open the Duo Mobile app on your phone.
- Tap the account you want a passcode for.
- Read the six-digit code displayed on the screen.
- Type that code into the login prompt of the service you are accessing.
The passcode refreshes every 30 seconds, so you must enter it before it changes. This method works even when you do not have an internet connection, since the code is generated locally on your device. Duo Mobile passcode method default policy setting is off for administrators.
How to approve Duo Push login requests
When you log into a service that uses Duo Push, a notification appears on your phone. Tap the notification to open Duo Mobile, then tap "Approve" to allow the login or "Deny" to block it. For passwordless logins, you may need to complete biometric verification (such as Face ID or fingerprint) or enter your device PIN or passcode before the approval goes through, depending on your browser and device trust state. If your organization requires mobile endpoints to be trusted, the app will also verify that your device meets security policies before allowing the login. Require mobile endpoints to be trusted is an administrator policy that prevents access from mobile endpoints failing MDM or Duo Mobile verification check.
Troubleshooting common Duo Mobile issues
Login requests not being received
If you stop receiving push notifications for login requests on Android, open the Duo Mobile app icon, go to App info → Notifications, and turn on All Duo Mobile notifications. On Android, enable notifications via App info → Notifications → All Duo Mobile notifications. On iPhone, ensure notifications are enabled for Duo Mobile in your device's Settings app under Notifications.
Inability to link Duo Mobile
If you cannot link Duo Mobile to your account, request a new activation link from your organization's security portal. If you have lost access to your old device, you may need to contact your IT support team to reset your enrollment and send a fresh activation link to your new phone.
Passcode generation failure
If Duo Mobile does not display a valid passcode, check that your device's time and date are set to automatic synchronization. Duo Mobile relies on accurate time for TOTP generation, and a mismatch of more than a few seconds will produce invalid codes.
Contacting customer support
If none of these steps resolve your issue, contact your organization's IT help desk or Duo customer support. Provide a detailed description of the problem, including any error messages you see, so they can assist you quickly.
Frequently Asked Questions
What is Duo Mobile used for?
Duo Mobile is used for two-factor authentication. It generates passcodes and receives push notifications that let you approve or deny login attempts, adding a second layer of security to your accounts.
How do I download Duo Mobile?
Download Duo Mobile from the Apple App Store for iPhone and iPad, or from Google Play for Android phones. Search for "Duo Mobile" and tap Install or Get.
Can I use Duo Mobile on multiple devices?
Yes, you can install Duo Mobile on multiple phones or tablets. Each device must be linked separately to your account using the same activation process, such as scanning the same QR code or entering the same setup key.
Is Duo Mobile compatible with all online services?
Duo Mobile works with any service that supports standard TOTP two-factor authentication, including many banks, email providers, and social media platforms. However, some services use proprietary authentication methods and may not be compatible. Check with the specific service to confirm support.
