It looks like you're trying to convert a cURL request to a Guzzle HTTP request in Laravel. The error you're encountering suggests that the grant_type parameter is not being sent correctly. In Guzzle (which Laravel's Http facade is based on), you don't need to specify 'form_params' as a key in the array when sending application/x-www-form-urlencoded requests. Instead, you should pass the form parameters directly as the second argument to the post method.
Here's how you can translate your cURL request to a Guzzle HTTP request using Laravel's Http facade:
use Illuminate\Support\Facades\Http;
$response = Http::withHeaders([
'Content-Type' => 'application/x-www-form-urlencoded',
'Authorization' => $this->authorization_header,
])->post('https://api.orange.com/oauth/v3/token', [
'grant_type' => 'client_credentials',
]);
echo $response->body();
Make sure to replace $this->authorization_header with the actual authorization header value you need to use.
This should correctly send the grant_type parameter in the body of the POST request as application/x-www-form-urlencoded. The echo $response->body(); will output the response body from the request.