I need to reactivate Duo Mobile

If you get a new phone you'll need to re-activate Duo Mobile. You may enroll your new device yourself using Duo's device management portal if self-service is enabled. Otherwise, ask your administrator to send you a new activation link.

Choose your platform on the left for specific activation instructions.

If your administrator enabled Duo Mobile's backup and restore functionality and you previously backed up your Duo Mobile accounts then you can restore your accounts to Duo Mobile on your new phone (same platform as the original device i.e. Android to Android and iOS to iOS) via the guided recovery process. See the full Duo Restore guide here.