m.twitch.tv not supported

[royale1223]

The mobile website of www.twitch.tv is not supported. Here's the error.

$ ./youtube-dl -F -v http://m.twitch.tv/beagsandjam/v/247478721
[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: [u'-F', u'-v', u'http://m.twitch.tv/beagsandjam/v/247478721']
[debug] Encodings: locale UTF-8, fs UTF-8, out UTF-8, pref UTF-8
[debug] youtube-dl version 2018.03.20
[debug] Lazy loading extractors enabled
[debug] Python version 2.7.14 (CPython) - Linux-4.13.0-38-generic-x86_64-with-Ubuntu-17.10-artful
[debug] exe versions: ffmpeg 3.3.4-2, ffprobe 3.3.4-2
[debug] Proxy map: {}
[generic] 247478721: Requesting header
[redirect] Following redirect to https://m.twitch.tv/beagsandjam/v/247478721
[generic] 247478721: Requesting header
WARNING: Falling back on generic information extractor.
[generic] 247478721: Downloading webpage
[generic] 247478721: Extracting information
ERROR: Unsupported URL: https://m.twitch.tv/beagsandjam/v/247478721
Traceback (most recent call last):
  File "./youtube-dl/youtube_dl/extractor/generic.py", line 2205, in _real_extract
    doc = compat_etree_fromstring(webpage.encode('utf-8'))
  File "./youtube-dl/youtube_dl/compat.py", line 2542, in compat_etree_fromstring
    doc = _XML(text, parser=etree.XMLParser(target=_TreeBuilder(element_factory=_element_factory)))
  File "./youtube-dl/youtube_dl/compat.py", line 2531, in _XML
    parser.feed(text)
  File "/usr/lib/python2.7/xml/etree/ElementTree.py", line 1659, in feed
    self._raiseerror(v)
  File "/usr/lib/python2.7/xml/etree/ElementTree.py", line 1523, in _raiseerror
    raise err
ParseError: not well-formed (invalid token): line 11, column 55
Traceback (most recent call last):
  File "./youtube-dl/youtube_dl/YoutubeDL.py", line 785, in extract_info
    ie_result = ie.extract(url)
  File "./youtube-dl/youtube_dl/extractor/common.py", line 440, in extract
    ie_result = self._real_extract(url)
  File "./youtube-dl/youtube_dl/extractor/generic.py", line 3143, in _real_extract
    raise UnsupportedError(url)
UnsupportedError: Unsupported URL: https://m.twitch.tv/beagsandjam/v/247478721