Signature extraction failed

[Khang-NT]

It works until today, I got this error: Signature extraction failed

Stacktrace:

[debug] System config: []
[debug] User config: []
[debug] Command-line args: [u'--verbose', u'kffacxfA7G4']
[debug] Encodings: locale UTF-8, fs UTF-8, out UTF-8, pref UTF-8
[debug] youtube-dl version 2016.06.20
[debug] Python version 2.7.11+ - Linux-4.4.0-24-generic-x86_64-with-Ubuntu-16.04-xenial
[debug] exe versions: avconv 2.8.6-1ubuntu2, avprobe 2.8.6-1ubuntu2, ffmpeg 2.8.6-1ubuntu2, ffprobe 2.8.6-1ubuntu2, rtmpdump 2.4
[debug] Proxy map: {}
[youtube] kffacxfA7G4: Downloading webpage
[youtube] kffacxfA7G4: Downloading video info webpage
[youtube] kffacxfA7G4: Extracting video information
[youtube] {43} signature length 40.43, html5 player en_US-vflkX1eCa
[youtube] kffacxfA7G4: Downloading player https://s.ytimg.com/yts/jsbin/player-en_US-vflkX1eCa/base.js
ERROR: Signature extraction failed: Traceback (most recent call last):
File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 997, in _decrypt_signature
video_id, player_url, s
File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 912, in _extract_signature_function
res = self._parse_sig_js(code)
File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 975, in _parse_sig_js
initial_function = jsi.extract_function(funcname)
File "/usr/lib/python2.7/dist-packages/youtube_dl/jsinterp.py", line 241, in extract_function
raise ExtractorError('Could not find JS function %r' % funcname)
ExtractorError: Could not find JS function u'ur'; 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.
(caused by ExtractorError(u"Could not find JS function u'ur'; 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.",)); 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/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 997, in _decrypt_signature
video_id, player_url, s
File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 912, in _extract_signature_function
res = self._parse_sig_js(code)
File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 975, in _parse_sig_js
initial_function = jsi.extract_function(funcname)
File "/usr/lib/python2.7/dist-packages/youtube_dl/jsinterp.py", line 241, in extract_function
raise ExtractorError('Could not find JS function %r' % funcname)
ExtractorError: Could not find JS function u'ur'; 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/python2.7/dist-packages/youtube_dl/YoutubeDL.py", line 676, in extract_info
ie_result = ie.extract(url)
File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/common.py", line 343, in extract
return self._real_extract(url)
File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 1570, in _real_extract
encrypted_sig, video_id, player_url, age_gate)
File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 1007, in _decrypt_signature
'Signature extraction failed: ' + tb, cause=e)
ExtractorError: Signature extraction failed: Traceback (most recent call last):
File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 997, in _decrypt_signature
video_id, player_url, s
File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 912, in _extract_signature_function
res = self._parse_sig_js(code)
File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 975, in _parse_sig_js
initial_function = jsi.extract_function(funcname)
File "/usr/lib/python2.7/dist-packages/youtube_dl/jsinterp.py", line 241, in extract_function
raise ExtractorError('Could not find JS function %r' % funcname)
ExtractorError: Could not find JS function u'ur'; 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.
(caused by ExtractorError(u"Could not find JS function u'ur'; 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.",)); 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.

Addition info:

$ youtube-dl --version 2016.06.20

[yan12125]

Duplicate of #9863. This is fixed in version 2016.06.23.1.