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Duo FAQs

Frequently Asked Questions

Duo Introduction
General questions about Duo.
What is Duo?

Duo is William & Mary’s two-factor authentication service. Two-factor authentication provides an additional level of security to help protect against increasingly sophisticated security threats.  It uses your W&M credentials plus a secondary authentication method (like a cell phone or office phone) to confirm your identity.

Why do I have to use Duo?

As data breaches become more common and security threats become more sophisticated, two-factor authentication has proven to be an effective way to thwart unauthorized access to accounts. Duo will help protect William & Mary’s university data and your personal data from being compromised.

Devices for Duo
Questions about Duo and your devices.
What devices are supported?
  • Duo app on a mobile device (iPhone, iPad, Android phone or Android tablet)
  • SMS passcodes
  • Telephone voice calls
  • Duo hardware tokens
I don't have a smartphone.
  1. You can use your office phone.
  2. If you have a basic mobile phone that only does text messaging (SMS) you can have a series of codes sent via text (SMS) message to your mobile phone.
  3. Hardware tokens (key fobs) are available upon request from the Technology Support Center.
Can I use a landline phone, like my office phone? 

Yes!  You can use landline phones for Duo.  It is highly recommended that you register both an office phone and a home phone during the enrollment process.

I don’t have an office phone. 

Not to worry! An office phone is not required. Cell phones are a good option for authenticating with Duo. 

What if I get a new phone?

If your phone number hasn't changed:

  1. Log in to
  2. Select Call Me to complete the Duo authentication
  3. Click Device Options
  4. Select Reactivate Duo Mobile
  5. Select your type of phone
  6. If you have not already done so, you will be prompted to download the Duo app on your new phone.
  7. Follow the instructions to re-enable the duo app on your new phone

You can also complete the process from the Duo Mobile App. Instructions:

If your phone number has changed, contact the Technology Support Center for assistance.

What if my Apple device shows a gray box or an "Application Not Authorized" CAS error?

Content restrictions on Apple devices can cause the Duo prompt to not display correctly. Either disable content restrictions or add as an exception to the content restrictions. More information is available from Duo.

Duo Mobile App
Questions about the Duo Mobile App.
Why should I use the Duo Mobile App?

It's all about ease of use.  As people generally carry smartphones with them most of the time, the Duo mobile app is the fastest, easiest, least-obtrusive way to authenticate with Duo.

There are other methods available (like a code sent via SMS, a landline phone, and a hardware token) but each of these methods come with limitations and/or an extra "thing to remember".

For the mobile app, why are the device permissions needed?

Duo needs permissions to access several functions on your phone.  For a complete explanation, see: 

Why does the mobile app need to access the camera on my phone?

During Duo enrollment, the camera is used to scan the Quick Response (QR) Code to connect the phone to your account.

You can remove this permission after enrollment. To disable the camera:

  1. Go to Settings
  2. Click Privacy
  3. Find Camera
  4. Toggle off Duo Mobile
I don’t want to put an app on my cell phone.
You can opt to have Duo send codes to your cellphone instead of downloading the app.  When you are enrolling, follow the instructions for Enrollment of a Mobile Phone without a Duo App.

Pushes & Codes
Questions about Duo push notifications.
Help!  I forgot my phone!

It's okay!  We have you covered. 

  1. Call the Technology Support Center (TSC) at 757-221-4357, or 1 + the last four digits if dialing from a classroom or residence hall public phone (1-HELP).
  2. After confirming your identify, you will receive a bypass code.  The code is valid for 24 hours.
  3. On the Duo login screen, click Enter a Passcode.
  4. Enter the code provided to you by the TSC.
  5. Optional:  Check the Remember Me... option in case you'd like to use other services that also require Duo.  You must use same device and browser for Duo to remember you.
  6. Click Log In.
What if I don't have wireless access or cellular phone service where I am?

From the Duo mobile app, use the caret icon to generate a passcode and type it in to the passcode box at the Duo login.

Duo passcode box


What if my Duo "push" times out?

You can reinitiate the push.

Or, from the Duo mobile app, you can use the caret icon to generate a passcode to type in to the passcode box at the Duo login.

Duo passcode box 

I have signed-up for auto-pushes, but the device that receives the "pushes" is not with me. What do I do?

Click the blue Cancel button.  A menu will appear with your registered methods of contact and you can select a different method for verification.  

Duo cancel button

My Duo hardware token isn't working

Duo hardware tokens may get out of sync with Duo if they are unused for a long period of time. They should resync with Duo if you use them 3 times consecutively - even if they fail the first two times. Third time's the charm!

Remember Me...
Questions about Duo Remember Me
Do I have to authenticate with Duo every time I login?

Duo 14 day reminder checkboxNo.  Check the Remember me for 14 days box on the Duo login prompt.  This will allow you to bypass Duo for 14 days if you are using the same device and browser to access applications.  

Why can't I click on the "Remember me..." checkbox?

If you have enabled a Duo push notification, you will first need to click the blue Cancel button. Then you can check the "Remember me" checkbox.

Certain applications, like VDI and VPN, will not offer the "Remember me" option.

Duo cancel button

What happens if I clear my cookies on my browser?

Duo will not be able to remember you if you clear your cookies in your web browser.  You will have to re-authenticate with Duo next time you log in to a Duo-enabled application. 

I don’t see the “Remember me...” option.

For security reasons, certain system do not offer the "Remember me..." option.  Those systems include the Duo Enrollment & Device Management site (, VDI (Virtual Desktops), and VPN. 

Can't click on the "Remember me..." option?

{{youtube:medium|MxcEkocsE74, We frequently hear that the "Remember me..." option is not available.  If Duo has sent out a Push (or if it is set to auto-push), you must first click on Cancel to activate the "Remember me..." checkbox.}}  

About Duo
Questions about Duo Mobile App.
What data does Duo collect?
Please refer to the Duo Knowledge Base.

Questions? Contact the Technology Support Center (TSC)
757-221-4357 (HELP) | [[support]] | Jones 201, Monday - Friday, 8:00 am - 5:00 pm