can't download from youtube

[kloro2006]

here is the output from the failed command:

tom@debianT1:~/Downloads$ youtube-dl --verbose https://www.youtube.com/watch?v=8rR_Q4kr_gk[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: ['--verbose', 'https://www.youtube.com/watch?v=8rR_Q4kr_gk']
[debug] Encodings: locale UTF-8, fs utf-8, out UTF-8, pref UTF-8
[debug] youtube-dl version 2017.05.18.1
[debug] Python version 3.5.3 - Linux-4.9.0-8-amd64-x86_64-with-debian-9.8
[debug] exe versions: ffmpeg 3.2.12-1, ffprobe 3.2.12-1, rtmpdump 2.4
[debug] Proxy map: {}
[youtube] 8rR_Q4kr_gk: Downloading webpage
[youtube] 8rR_Q4kr_gk: Downloading video info webpage
ERROR: 8rR_Q4kr_gk: "token" parameter not in video info for unknown reason; please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; see https://yt-dl.org/update on how to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.
Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/youtube_dl/YoutubeDL.py", line 760, in extract_info
ie_result = ie.extract(url)
File "/usr/lib/python3/dist-packages/youtube_dl/extractor/common.py", line 433, in extract
ie_result = self._real_extract(url)
File "/usr/lib/python3/dist-packages/youtube_dl/extractor/youtube.py", line 1502, in _real_extract
video_id=video_id)
youtube_dl.utils.ExtractorError: 8rR_Q4kr_gk: "token" parameter not in video info for unknown reason; please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; see https://yt-dl.org/update on how to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.

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