Vimeo API-无法启动上传

Question

尝试将视频上传到viemo时出现问题

这是我的代码

$file_name = "video.mp4";

$file_name = realpath($file_name);

$uri = $client->upload($file_name, array(
    "name" => "New Video",
    "description" => "10 seconds video for testing"
));

echo "Your video URI is: " + $uri;

我收到此错误Fatal error: Uncaught Vimeo\Exceptions\VimeoUploadException: Unable to initiate an upload.

您能帮我解决此问题吗？