DocuSignAPI REST - Why won't my OAuth request go through? - docusignapi

Question

I'm attempting to use the DocuSign REST API and create an OAuth request to execute Send of Behalf of (SOBO). Although I can't complete the first task, it's giving me back a Bad Request. What am I doing wrong?
Request with Headers:
POST https://demo.docusign.net/restapi/v2/oauth2/token
Accept: application/xml
Content-Type: application/xml
Content-Length: {length of body}
Request Body
<OAuthTokenRequest>
<grant_type>password</grant_type>
<client_id>{IntegratorKey}</client_id>
<username>test#email.com</username>
<password>{Password}</password>
<scope>api</scope>
</OAuthTokenRequest>
Response with Error:
400 Bad Request
<oauthErr xmlns="http://www.docusign.com/restapi" xmlns:i="http://www.w3.org/2001/XMLSchema-instance">
<error>invalid_request</error>
<error_description>An OAuth2 error occurred:</error_description>
</oauthErr>

Answer 1

Although most of the DocuSign REST API accepts XML formatting, OAuth requests must be made in x-www-form-urlencoded.
Change your request to the following:
Request with Headers:
POST https://demo.docusign.net/restapi/v2/oauth2/token
Accept: application/xml
Content-Type: application/x-www-form-urlencoded
Content-Length: {length of body}
Request Body:
grant_type=password&client_id={IntegratorKey}&username=test#email.com&password={Password}&scope=api
Sample Response:
200 OK
<oauthAccess xmlns="http://www.docusign.com/restapi" xmlns:i="http://www.w3.org/2001/XMLSchema-instance">
<access_token>{Access Token}</access_token>
<scope>api</scope>
<token_type>bearer</token_type>
</oauthAccess>
More information can be obtained in this documentation.