To get the Hydra access token, you need to hit the

/oauth2/token

endpoint as described in the [Hydra API Reference](https://www.ory.sh/docs/hydra/reference/api). The request body you provided seems to be correct for an OAuth2 authorization code grant request. However, the error message indicates that the request body is not being sent or is empty. In React, you can use the

fetch

API to send a POST request to the

/oauth2/token

endpoint. Here's an example:

javascript fetch('<https://your-hydra-instance.com/oauth2/token>', {   method: 'POST',   headers: {     'Content-Type': 'application/x-www-form-urlencoded',   },   body: new URLSearchParams({     client_id: 'myclient',     code: 'ory_ac_7pNZ-yfOsWY5timqd7jvAQtlK5G0pQBlTHYeWSyuAcM.7Xb5rqU8A_xyyZWynBL1ObB-UCfth4b_Nc992Qt7rV4',     grant_type: 'authorization_code',     redirect_uri: '<http://localhost:3000/callbacks>',   }), }) .then(response => response.json()) .then(data => console.log(data)) .catch((error) => console.error('Error:', error));

Please replace

'<https://your-hydra-instance.com/oauth2/token>'

with your actual Hydra instance URL. The error message you're seeing usually means that the POST body is not being sent or is empty. Make sure that you're correctly setting the

Content-Type

header to

application/x-www-form-urlencoded

and that you're correctly URL encoding the parameters in the body of the request. As for the refresh token, it is usually a long, random string that is issued by the authorization server (in this case, Hydra) when the access token is issued. The exact value will depend on the configuration of your Hydra instance. You can use this refresh token to get a new access token when the current one expires, without needing the user to authenticate again.