Express returning 200 even if error from server

Question

I am trying to connect to a third party endpoint from my express app. With specific body Doing the same request in curl directly to that endpoint gives me a 400 status with a specific error message.

Now using express + node-fetch, I am getting the error message, but I get 200 status code.

export async function authenticate() {
  const result =  await fetch(`${config.host}/token`, {
    method: 'POST',
    headers: {
      'Content-Type': 'application/x-www-form-urlencoded'
    },
    body: JSON.stringify({
        key: "someValueThatShouldReturnError"
    })
  });
  console.log(result.status); // this prints 400
  const json = await result.json();
  return json;
}

And in the router I have

router.post('/auth', handleErrorAsync(async(req: any, resp: Response, err: any) => {
  let res = await authenticate();
  resp.send(res);
}));

a temporary solution is to add this in the async function after declaring json variable..But I feel this should be handled out of the box.

  if (result.status !== 200) {
    throw createError(result.status, json.error);
  }