微信支付APIv3充分复用了HTTP状态码来反馈接口响应状态，PHP SDK readme上有写，对于同步代码，需要用try {} catch(){} 语句包裹，异步可以用otherwise捕获，例如：

try {

$response = $instance->chain('v3/fund-app/mch-transfer/transfer-bills')->post([
  'json' => [
    'appid'                       => 'wxf636efh567hg4356',
    'out_bill_no'                 => 'plfk2020042013',
    'openid'                      => 'o-MYE42l80oelYMDE34nYD456Xoy',
    'user_name'                   => '757b340b45ebef5467rter35gf464344v3542sdf4t6re4tb4f54ty45t4yyry45',
    'transfer_amount'             => 400000,
    'transfer_remark'             => '2020年4月报销',
    'notify_url'                  => 'https://www.weixin.qq.com/wxpay/pay.php',
    'user_recv_perception'        => '现金奖励',
    'transfer_scene_id'           => '1000',
    'transfer_scene_report_infos' => [[
      'info_type'    => '活动名称',
      'info_content' => '注册会员有礼',
    ],],
  ],
  'headers' => [
    'Wechatpay-Serial' => 'PUB_KEY_ID_0114232134912410000000000000',
  ],
]);
print_r(json_decode((string) $response->getBody(), true));

} catch (\Exception $e) {
    // 进行错误处理
    echo $e->getMessage(), PHP_EOL;
    if ($e instanceof \GuzzleHttp\Exception\RequestException && $e->hasResponse()) {
        $r = $e->getResponse();
        echo $r->getStatusCode() . ' ' . $r->getReasonPhrase(), PHP_EOL;
        echo (string) $r->getBody(), PHP_EOL, PHP_EOL, PHP_EOL;
    }
    echo $e->getTraceAsString(), PHP_EOL;
}

异步方式

$instance->chain('v3/fund-app/mch-transfer/transfer-bills')->postAsync([
  'json' => [
    'appid'                       => 'wxf636efh567hg4356',
    'out_bill_no'                 => 'plfk2020042013',
    'openid'                      => 'o-MYE42l80oelYMDE34nYD456Xoy',
    'user_name'                   => '757b340b45ebef5467rter35gf464344v3542sdf4t6re4tb4f54ty45t4yyry45',
    'transfer_amount'             => 400000,
    'transfer_remark'             => '2020年4月报销',
    'notify_url'                  => 'https://www.weixin.qq.com/wxpay/pay.php',
    'user_recv_perception'        => '现金奖励',
    'transfer_scene_id'           => '1000',
    'transfer_scene_report_infos' => [[
      'info_type'    => '活动名称',
      'info_content' => '注册会员有礼',
    ],],
  ],
  'headers' => [
    'Wechatpay-Serial' => 'PUB_KEY_ID_0114232134912410000000000000',
  ],
])
->then(static function(\Psr\Http\Message\ResponseInterface $response) {
  print_r(json_decode((string) $response->getBody(), true));
})
->otherwise(static function($e) {
    // 异常错误处理
    echo $e->getMessage(), PHP_EOL;
    if ($e instanceof \GuzzleHttp\Exception\RequestException && $e->hasResponse()) {
        $r = $e->getResponse();
        echo $r->getStatusCode() . ' ' . $r->getReasonPhrase(), PHP_EOL;
        echo (string) $r->getBody(), PHP_EOL, PHP_EOL, PHP_EOL;
    }
    echo $e->getTraceAsString(), PHP_EOL;
});
->wait();

代码可以从 https://wechatpay.im/openapi/v3/fund-app/mch-transfer/transfer-bills CV

403是没有权限，把返回的body打印出来，里面有具体错误