public function requestCredentialsToken()
    {
        $payload = base64_encode($this->getClientId() . ':' . $this->getClientSecret());

        $parameters = [
            'grant_type' => 'client_credentials',
        ];

        $headers = [
            'Authorization' => 'Basic ' . $payload,
        ];

        $response = $this->request->account('POST', '/api/token', $parameters, $headers);
        $response = $response['body'];

        if (isset($response->access_token)) {
            $this->accessToken = $response->access_token;
            $this->expirationTime = time() + $response->expires_in;
            $this->scope = isset($response->scope) ? $response->scope : $this->scope;

            return true;
        }

        return false;
    }