# 40015: Invalid device ID

Identifier: `invalid_device_id`



The device ID supplied for a push notification operation was missing or not in an acceptable form, so the request was rejected.

## What you should do

Send a valid device ID with the request. The `id` in the `DeviceDetails` object must be present and a string. Correct it and retry. See [push notifications](https://ably.com/docs/push.md) for how devices are registered.

## Why it happens

The device ID supplied when registering or updating a device for push notifications was missing or not a string, so the request was rejected.

## What you'll see

The error is reported with code 40015 and HTTP status 400. The message is typically `Invalid deviceId`.