# 97001: Unable to retrieve OAuth access token

Log Type: APPLICATION

Log Level: ERROR

## Description

Twilio will start dropping webhooks until the authorization server provides a valid token.

### Possible causes

* The authorization service is unavailable.
* The authorization service is unreachable.
* The client credentials you configured have been rotated or removed.
* The authorization server has started issuing a token which is not of type `Bearer`.

### Possible solutions

* Verify your authorization server is running and healthy.
* Verify your authorization server is not protected by a firewall which blocks the requests.
* Update the webhook settings with valid client credentials.
* Update the webhook settings to disable OAuth.
* Verify the authorization server issues tokens of type `Bearer`.