## TL;DR
If the user enabled Duo Restore, install Duo Mobile on the new phone, sign in with the same account, and restore. If not, an admin issues a bypass code or sends a reactivation link via SMS; the user then re-activates Duo Mobile on the new device.

## The error
```text
(Users select "Send a Duo Push" and nothing arrives on the new phone.)
```

## Steps
1. Ask if the old phone is available. If yes: on the old phone, Duo Mobile > Settings > Duo Restore > back up now. Expected: backup completes. Then restore on the new phone.
2. If the old phone is gone: Duo admin panel > Users > the user > Phones > Reactivate Duo Mobile. Expected: an SMS with a reactivation link goes to the user's number.
3. The user taps the link on the NEW phone and follows the activation. Expected: Duo Mobile activates and a test push arrives.
4. If the phone number also changed: update the number on the user's phone record first, then reactivate. Expected: SMS reaches the new number.
5. As an immediate unblock, generate a bypass code: Users > the user > Bypass Codes > Add. Expected: a single-use code the user can enter at the Duo prompt right now.

## When to use
- New phone, Duo pushes stopped
- Old phone lost, broken, or wiped

## When not to use
- First-time Duo enrollment (use the enrollment link flow)
- Duo Push arrives but approval fails (check time sync)

## Compatibility
- Duo MFA (Duo Admin Panel); Duo Mobile on iOS/Android

## Variants
### Reactivation link expired
Links expire quickly. Generate a fresh one; do not keep resending the old SMS.
### User has no cellular service on the new phone yet
Use a bypass code over another channel, or activate over Wi-Fi with the link.

## Why it happens
Duo's device identity is bound to the phone installation, not just the account. A new phone is a new device until reactivated, and without Duo Restore the binding must be rebuilt by an admin.

## Edge cases
- Users who factory-reset without backup: same as a lost phone; admin reactivation required.
- Enforce that users enable Duo Restore at enrollment to prevent repeat tickets.

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_3HWZQ951ngsCEsB_rMAbUw