# Auth Hooks: 'Invalid payload' when anonymous users attempt phone changes

An 'Invalid payload sent to hook' error (500) occurs in Auth hooks when the payload includes `new_phone` for an anonymous user.

## Why does this happen?

This error arises because anonymous users do not have an existing phone number to modify. Client application logic attempting a `phone_change` for such users results in an invalid operation. The `new_phone` field should only be present during a `phone_change` flow initiated by an *authenticated* user.

## How to avoid this issue

Refine your client application logic to prevent this incorrect payload structure:

- Differentiate phone update and login flows for anonymous users from authenticated users.
- Ensure `new_phone` is only transmitted when an authenticated user initiates a `phone_change` flow.
- Implement distinct handling for anonymous user updates to avoid sending `new_phone` in the payload.