viki can not download video now？

[hucaloof]

[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: [u'-v', u'--restrict-filenames', u'-o', u'/data/viki/zuijiaqiannanyou/%(title)s.%(ext)s', u'--proxy', u'http://138.68.16.252:3128', u'https://www.viki.com/tv/28818c-my-best-ex-boyfriend#modal-episode']
[debug] Encodings: locale UTF-8, fs UTF-8, out UTF-8, pref UTF-8
[debug] youtube-dl version 2017.09.11
[debug] Git HEAD: fd0b8fc
[debug] Python version 2.7.13 - Linux-2.6.32-431.el6.x86_64-x86_64-with-centos-6.5-Final
[debug] exe versions: ffmpeg 3.3.3, ffprobe 3.3.3, rtmpdump 2.3
[debug] Proxy map: {u'http': u'http://138.68.16.252:3128', u'https': u'http://138.68.16.252:3128'}
[viki:channel] 28818c: Downloading channel JSON
[viki:channel] 28818c: Downloading episodes JSON page #1
[viki:channel] 28818c: Downloading episodes JSON page #2
[viki:channel] 28818c: Downloading clips JSON page #1
[viki:channel] 28818c: Downloading movies JSON page #1
[download] Downloading playlist: My Best Ex-Boyfriend
[viki:channel] playlist My Best Ex-Boyfriend: Collected 55 video ids (downloading 55 of them)
[download] Downloading video 1 of 55
[viki] 1077337v: Downloading video JSON
[viki] 1077337v: Downloading video streams JSON
ERROR: viki returned error: invalid signature
Traceback (most recent call last):
  File "/root/.pyenv/versions/2.7.13/envs/env27/lib/python2.7/site-packages/youtube_dl/YoutubeDL.py", line 776, in extract_info
    ie_result = ie.extract(url)
  File "/root/.pyenv/versions/2.7.13/envs/env27/lib/python2.7/site-packages/youtube_dl/extractor/common.py", line 434, in extract
    ie_result = self._real_extract(url)
  File "/root/.pyenv/versions/2.7.13/envs/env27/lib/python2.7/site-packages/youtube_dl/extractor/viki.py", line 270, in _real_extract
    'Downloading video streams JSON')
  File "/root/.pyenv/versions/2.7.13/envs/env27/lib/python2.7/site-packages/youtube_dl/extractor/viki.py", line 69, in _call_api
    self._raise_error(resp['error'])
  File "/root/.pyenv/versions/2.7.13/envs/env27/lib/python2.7/site-packages/youtube_dl/extractor/viki.py", line 76, in _raise_error
    expected=True)
ExtractorError: viki returned error: invalid signature