Creating new address on shippo gives 500 error

Question

I am creating a new address using shippo api using test token and when i give the array of address and click create it gives me 500 error. I am doing everything according to the docs given by shippo here is my code that I am using. The request I am sending is through ajax.

require_once ABSPATH . '/shippo/shippo/lib/Shippo';
    Shippo::setApiKey("test_token");
    $address = Shippo_Address::
            create(
                    array(
                        'object_purpose' => 'QUOTE',
                        'name' => 'John Smith',
                        'company' => 'Initech',
                        'street1' => '6512 Greene Rd.',
                        'city' => 'Woodridge',
                        'state' => 'IL',
                        'zip' => '60517',
                        'country' => 'US',
                        'phone' => '773 353 2345',
                        'email' => 'jmercouris@iit.com',
                        'metadata' => 'Customer ID 23424'
    ));
    var_dump($address);

I am confuse that what is it that I am doing wrong or missing?