ERROR: Unable to extract sts

[japzone1]

Was trying to grab The Witcher 3 trailer when I got this error. Tried other videos and they worked fine. This one consistently doesn't work though. However I can download the video with the Youtube Center Greasemonkey script.

[debug] System config: []
[debug] User config: []
[debug] Command-line args: ['--verbose', 'http://youtube.com/watch?v=HtVdAasjOgU']
[debug] Encodings: locale cp1252, fs mbcs, out None, pref cp1252
[debug] youtube-dl version 2014.10.30
[debug] Python version 2.7.8 - Windows-8-6.2.9200
[debug] exe versions: ffmpeg N-66929-, ffprobe N-66929-
[debug] Proxy map: {}
ERROR: Unable to extract sts; please report this issue on https://yt-dl.org/bug . Be sure to call youtube-dl with the --verbose flag and include its complete output. Make sure you are using the latest version; type  youtube-dl -U  to update.
Traceback (most recent call last):
  File "youtube_dl\YoutubeDL.pyo", line 533, in extract_info
  File "youtube_dl\extractor\common.pyo", line 198, in extract
  File "youtube_dl\extractor\youtube.pyo", line 697, in _real_extract
  File "youtube_dl\extractor\common.pyo", line 432, in _search_regex
RegexNotFoundError: Unable to extract sts; please report this issue on https://yt-dl.org/bug . Be sure to call youtube-dl with the --verbose flag and include its complete output. Make sure you are using the latest version; type  youtube-dl -U  to update.

[clampak]

As it says in the error message, update to the latest version and see if that works. youtube-dl -U

[japzone1]

Yeah I'm stupid. Though youtube-dl -U never works for me on Windows so I have to download it manually.

[martinswacke]

It seems YouTube does not include STS parameter in the webpage anymore. So it is missing always and for age gated videos with ciphered signatures you will get response 403: Forbidden.
Here is an example video: http://www.youtube.com/watch?v=07FYdnEawAQ

[jaimeMF]

I'm closing the issue, it works in the last version.
@martinswacke, see #4108.