I do not have my phone on hand. How to get around the 2FA login prompt?


Applies to

Students and Staff



It just so happens that you don't have your mobile phone for responding to 2FA push messages.  Fortunately, you can get around this by using a bypass code.  This article illustrates the complete process step-by-step.


  1. Visit https://duo.itsc.cuhk.edu.hk/ and sign in using any web browser.

  2. After signed-in, click BYPASS CODE tab > I HAVE A VALID CU LINK CARD ON HAND. > START

  3. Follow the on-screen instructions to input your CU Link Serial Number.  Respond to the CAPTCHA and click GET BYPASS CODE.

  4. Your Bypass Code will be shown on screen after your CU Link Serial Number is validated.  Please keep it in a safe place.

  5. Go back to the application you would like to sign in (e.g. email).  Click Other Options.


  6.  Choose Bypass Code.


  7.  Then enter the Bypass Code and click Verify



Don't have CU Link Card or it is Expired?

Please check if you still have the rescue code saved when you first enroll into 2FA.  If so, you can use it to generate the Bypass Code by following the steps below:

  1. Visit https://duo.itsc.cuhk.edu.hk/ using any web browser.
  2. After signed-in, click BYPASS CODE tab > I HAVE A RESCUE CODE ON HAND. > START

Otherwise, please contact us for assistance on your 2FA enrollment and attach a copy of your expired student card / identity document showing your full name and photo (please MASK/HIDE other sensitive information) for identity verification.


My CU Link card cannot be verified?

Earlier versions of CU Link cards with only 10 characters of serial number may not be able to pass the bypass code verification.  In this case, please visit CU Link Card Centre for card re-issuance and contact us if you need assistance on your 2FA enrollment.


#Don't have phone #Forget to bring my phone