Unity WebGL错误网络::错误中止404(未找到)

在这个项目中,我有一个从互联网上下载视频的协同程序

IEnumerator DownloadVideo(string video_download_link){
    UnityWebRequest www = UnityWebRequest.Get(video_download_link);
    yield return www.SendWebRequest();
    string savePath = Application.temporaryCachePath + "/myVideo.mp4";
    File.WriteAllBytes(savePath, www.downloadHandler.data);

    yield return new WaitUntil(() => File.Exists(savePath));
    videoPlayer.url = savePath;
    videoPlayer.Prepare();
    while(!videoPlayer.isPrepared) yield return null;
    videoPlayer.Play();
}

视频似乎下载得很好,但在播放时,我得到:

得到 http://www.mywebsite.com/tmp/myVideo.mp4 net::ERR_中止404(未找到)

我做错什么了?我该怎么解决这个问题?