I had Duo Mobile set up on my smartphone already, but it is no longer working. What can I do?

In order to fix this issue, please re-enroll your device. Ensure you have backup passcodes ready, and then delete the Duo application from your phone. Reinstall it as a new device – instructions can be found on the 2-step page of our website: https://calnet.berkeley.edu/calnet-2-step/2-step-devices