What is the correct way to send application/x-www-form-urlencoded with axios?

I am following the documentation provided here: https://github.com/axios/axios?tab=readme-ov-file#using-applicationx-www-form-urlencoded-format

async function loginAuth(code: string) {
  try {
    const params = new URLSearchParams({
      grant_type: "authorization_code",
      code,
      client_id: process.env.COGNITO_CLIENT_ID,
      redirect_uri: process.env.COGNITO_REDIRECT_URL,
    });
    const response = await axios.post(
      `https://${process.env.COGNITO_CLIENT_NAME}.auth.us-east-1.amazoncognito.com/oauth2/token`,
      params,
      {
        headers: {
          Authorization: `Basic ${process.env.COGNITO_AUTHENTICATION}`,
          "Content-Type": "application/x-www-form-urlencoded",
        },
      }
    );
    return response.data;
  } catch (e) {
    console.error(`Error with loginAuth: ${JSON.stringify(e)}`);
    return null;
  }
}

However, this returns in a 400. The complete error, along with the request that is sent is given below. I have replaced the secrets with dummy text, but they are correct.

{
    "message": "Request failed with status code 400",
    "name": "AxiosError",
    "stack": "AxiosError: Request failed with status code 400n    at settle (/Users/rahul/code/helix-transition_graphql/packages/api/node_modules/axios/lib/core/settle.js:19:12)n    at IncomingMessage.handleStreamEnd (/Users/rahul/code/helix-transition_graphql/packages/api/node_modules/axios/lib/adapters/http.js:589:11)n    at IncomingMessage.emit (node:events:531:35)n    at IncomingMessage.emit (node:domain:488:12)n    at endReadableNT (node:internal/streams/readable:1696:12)n    at processTicksAndRejections (node:internal/process/task_queues:82:21)n    at Axios.request (/Users/rahul/code/helix-transition_graphql/packages/api/node_modules/axios/lib/core/Axios.js:45:41)n    at processTicksAndRejections (node:internal/process/task_queues:95:5)",
    "config": {
        "transitional": {
            "silentJSONParsing": true,
            "forcedJSONParsing": true,
            "clarifyTimeoutError": false
        },
        "adapter": [
            "xhr",
            "http",
            "fetch"
        ],
        "transformRequest": [
            null
        ],
        "transformResponse": [
            null
        ],
        "timeout": 0,
        "xsrfCookieName": "XSRF-TOKEN",
        "xsrfHeaderName": "X-XSRF-TOKEN",
        "maxContentLength": -1,
        "maxBodyLength": -1,
        "env": {},
        "headers": {
            "Accept": "application/json, text/plain, */*",
            "Content-Type": "application/x-www-form-urlencoded",
            "Authorization": "Basic <dummy_token>",
            "User-Agent": "axios/1.7.2",
            "Content-Length": "158",
            "Accept-Encoding": "gzip, compress, deflate, br"
        },
        "method": "post",
        "url": "dummy_url",
        "data": "grant_type=authorization_code&code=dummy_code&client_id=dummy_idredirect_uri=http%3A%2F%2Flocalhost%3A3000%2Fauth"
    },
    "code": "ERR_BAD_REQUEST",
    "status": 400
}

If I use the package request, the code works without any issue.

function loginAuth(code: string) {
  return new Promise((resolve, reject) => {
    const options = {
      method: "POST",
      url: `https://${process.env.COGNITO_CLIENT_NAME}.auth.us-east-1.amazoncognito.com/oauth2/token`,
      headers: {
        Authorization: `Basic ${process.env.COGNITO_AUTHENTICATION}`,
        "Content-Type": "application/x-www-form-urlencoded",
      },
      form: {
        grant_type: "authorization_code",
        code,
        client_id: process.env.COGNITO_CLIENT_ID,
        redirect_uri: process.env.COGNITO_REDIRECT_URL,
      },
    };

    request(options, (error, response) => {
      if (error) {
        reject(error);
        return;
      }
      resolve(response.body);
    });
  });
}

Can someone tell me what I am doing wrong with Axios?