What is the right way to write JSON parameter to send a Guzzle POST request in Laravel?

I need to send a post request to an api endpoint. While I try with Guzzle I get an error that says the method not allowed

 Client error: `POST https://api.***.com/v2/ ` resulted in a `405 Method Not Allowed` response: { "error": { "type": "method-not-allowed", "message": "This API end-point can only be accessed using the follo (truncated...)

But when I try with Ajax it works fine.

Here is the Guzzle code:

  $headers = [
        'Content-Type' => 'application/json',
    ];
    $client = new Client(['headers' => $headers]);

    $response = $client->post('https://api.***.com/v2/' , [
        'json' =>  ["queries" => "Online MBA" ]
    ]);

Here is the call from Ajax

     $.ajax({
             url : 'https://***/runs?***',
             method : 'POST',
             contentType: 'application/json',
             dataType: 'json',
             data : JSON.stringify ({
                        "queries" : "Online MBA"
                    }),
             success:function(result) {
                        console.log(result);
                     } 

        });

Is the problem in the following code?

'json' =>  ["queries" => "Online MBA" ]

via Chebli Mohamed