> ## Documentation Index
> Fetch the complete documentation index at: https://developer.box.com/llms.txt
> Use this file to discover all available pages before exploring further.
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# Client Credentials Grant
export const SignupCTA = ({children}) => {
return
;
};
export const Link = ({href, children, className, ...props}) => {
const localizedHref = href;
return
{children}
;
};
Follow the steps below if you would like to leverage server authentication and
verify your application's identity using a client ID and client secret.
## Prerequisites
* A Platform Application using Server Authentication (with Client Credentials Grant) authentication in the Box [Developer Console][devconsole]
* [2FA][2fa] enabled on your Box account for viewing and copying the application's client secret from the configuration tab
* The application is authorized in the Box Admin Console
A free developer account gives you access to the Developer Console, where you can set up Client Credentials Grant authentication in minutes.
Your client secret is confidential and needs to be protected. Because this is
how we securely identify an application's identity when obtaining an
Access Token, you do not want to freely distribute a client secret. This
includes via email, public forums and code repositories, distributed native
applications, or client-side code. If you would like to add more security
mechanisms, we recommend using our standard JWT application type.
## How to use
When making your API call to obtain an Access Token, your
request body needs to contain your client ID and client Secret. Set the
`grant_type` to `client_credentials`.
If you would like to authenticate as the application's Service Account:
* set `box_subject_type` to `enterprise`
* set `box_subject_id` to the enterprise ID
If you would like to authenticate as an admin or a managed user:
* set `box_subject_type` to `user`
* set `box_subject_id` to the user ID
* enable **App + Enterprise Access** and **Generate User Access Tokens** Box [Developer Console][devconsole]
If you would like to authenticate as any application user:
* set `box_subject_type` to `user`
* set `box_subject_id` to the user ID
* enable **Generate User Access Tokens** in the Box [Developer Console][devconsole]
## Common Errors
### Grant credentials are invalid
During authentication, you can encounter the following error:
```sh theme={null}
Grant credentials are invalid [400 Bad Request] invalid_grant - Grant credentials are invalid
```
This error indicates either:
* the client ID and client secret passed are incorrect or are not for the same application,
* the `box_subject_id` cannot be used based on the selected application access.
A CCG app with App Access Only can send in the `box_subject_type` of `enterprise` to authenticate as its service account, but it can't authenticate as a managed user or an admin.
* to use a `box_subject_type` of `user`, your application should be configured to generate user access tokens in the **Advanced Features** section of the **Configuration tab**.
Once you make changes to the app settings, don't forget to reauthorize the application in the Admin Console.
* your application has not been authorized in the Box Admin Console
[2fa]: https://support.box.com/hc/en-us/articles/360043697154-Two-Factor-Authentication-Set-Up-for-Your-Account
[devconsole]: https://app.box.com/developers/console
