Assistance Required: 400 Bad Request Error When Requesting OAuth

[cesar-gordillo]

Hello,

I am encountering an issue while trying to obtain an OAuth token using Postman. I am following the Coupa API documentation, but my request is returning a “400 Bad Request” error. I would appreciate your assistance in resolving this issue.

Objective:
I am trying to authenticate with Coupa’s OAuth service to obtain an access token, which I need to make authenticated API requests.

Request Details

Body: Here is the information from outside of Postman which correct with my body inside of postman

Error Received:
When sending the request, I receive the following response:

Troubleshooting Steps Taken:

1. Verified the endpoint URL and headers.
2. Checked the parameters and ensured they are URL-encoded.
3. Referenced Coupa’s OAuth documentation to confirm correct parameter usage.

Not sure if I am missing a step, any guidance would help.

[michaelderekjones (Mike Jones)]

Based on this documentation.

OpenID Connect Clients | Coupa

Importing the cURL request into Postman. The request you are sending looks correct.

400 bad request status codes normally indicate that the request itself is malformed, not that the data sent is incorrect, which would normally produce a different error related to authentication.

The only thing I can suggest is to pare back the list of scopes and try authenticating with a single scope. Does that make any difference?

Also check the console logs to see what is being sent. Does the request look correct there.