Android Volley gives me 400 error

I'm trying to make a `POST` request to my API and it works in `Postman` (I get a valid JSON object), but not using `Volley`. With the following code: ``` String URL = "http://somename/token"; RequestQueue queue = Volley.newRequestQueue(StartActivity.this); queue.add(new JsonObjectRequest(Method.POST, URL, null, new Listener<JSONObject>() { @Override public void onResponse(JSONObject response) { // handle response Log.i("StartActivity", response.toString()); } }, new ErrorListener() { @Override public void onErrorResponse(VolleyError error) { // handle error Log.i("StartActivity", error.toString()); } }) { @Override public Map<String, String> getHeaders() throws AuthFailureError { HashMap<String, String> headers = new HashMap<String, String>(); headers.put("username", "someUsername"); headers.put("password", "somePassword"); headers.put("Authorization", "Basic someCodeHere"); return headers; } @Override protected Map<String,String> getParams(){ Map<String,String> params = new HashMap<String, String>(); params.put("grant_type", "client_credentials"); return params; } }); ``` I get the following error: ``` 02-12 21:42:54.774: E/Volley(19215): [46574] BasicNetwork.performRequest: Unexpected response code 400 for http://somename/token/ ``` I have seen a lot of examples and I don't really see what is going wrong here. Anyone any idea? I updated the code with this method: ``` HashMap<String, String> createBasicAuthHeader(String username, String password) { HashMap<String, String> headerMap = new HashMap<String, String>(); String credentials = username + ":" + password; String base64EncodedCredentials = Base64.encodeToString(credentials.getBytes(), Base64.NO_WRAP); headerMap.put("Authorization", "Basic " + base64EncodedCredentials); return headerMap; } ``` and changed `getHeaders()` to: ``` @Override public Map<String, String> getHeaders() throws AuthFailureError { return createBasicAuthHeader("username", "password"); } ``` Still getting the same error!