Repository: youtube-dl
Issue: oreilly login page error
Labels: broken-IE

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## Checklist

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Carefully read and work through this check list in order to prevent the most common mistakes and misuse of youtube-dl:
- First of, make sure you are using the latest version of youtube-dl. Run `youtube-dl --version` and ensure your version is 2021.12.17. If it's not, see https://yt-dl.org/update on how to update. Issues with outdated version will be REJECTED.
- Make sure that all provided video/audio/playlist URLs (if any) are alive and playable in a browser.
- Make sure that all URLs and arguments with special characters are properly quoted or escaped as explained in http://yt-dl.org/escape.
- Search the bugtracker for similar issues: http://yt-dl.org/search-issues. DO NOT post duplicates.
- Read bugs section in FAQ: http://yt-dl.org/reporting
- Finally, put x into all relevant boxes (like this [x])
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- [ x ] I'm reporting a broken site support issue
- [ x ] I've verified that I'm running youtube-dl version **2021.12.17**
- [ x ] I've checked that all provided URLs are alive and playable in a browser
- [ x ] I've checked that all URLs and arguments with special characters are properly quoted or escaped
- [ x ] I've searched the bugtracker for similar bug reports including closed ones
- [ x ] I've read bugs section in FAQ


## Verbose log

<!--
Provide the complete verbose output of youtube-dl that clearly demonstrates the problem.
Add the `-v` flag to your command line you run youtube-dl with (`youtube-dl -v <your command line>`), copy the WHOLE output and insert it below. It should look similar to this:
 [debug] System config: []
 [debug] User config: []
 [debug] Command-line args: [u'-v', u'http://www.youtube.com/watch?v=BaW_jenozKcj']
 [debug] Encodings: locale cp1251, fs mbcs, out cp866, pref cp1251
 [debug] youtube-dl version 2021.12.17
 [debug] Python version 2.7.11 - Windows-2003Server-5.2.3790-SP2
 [debug] exe versions: ffmpeg N-75573-g1d0487f, ffprobe N-75573-g1d0487f, rtmpdump 2.4
 [debug] Proxy map: {}
 <more lines>
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```
[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: [u'-u', u'PRIVATE', u'-p', u'PRIVATE', u'--verbose', u'--write-info-json', u'https://learning.oreilly.com/videos/linux-shell-scripting/9781789800906/']
[debug] Encodings: locale UTF-8, fs UTF-8, out UTF-8, pref UTF-8
[debug] youtube-dl version 2021.12.17
[debug] Python version 2.7.16 (CPython) - Linux-4.19.0-18-cloud-amd64-x86_64-with-debian-10.12
[debug] exe versions: ffmpeg 4.1.8-0, ffprobe 4.1.8-0
[debug] Proxy map: {}
[safari:course] Downloading login page
ERROR: An extractor error has occurred. (caused by KeyError(u'next',)); please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; type  youtube-dl -U  to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.
Traceback (most recent call last):
  File "/usr/local/bin/youtube-dl/youtube_dl/extractor/common.py", line 533, in extract
    self.initialize()
  File "/usr/local/bin/youtube-dl/youtube_dl/extractor/common.py", line 437, in initialize
    self._real_initialize()
  File "/usr/local/bin/youtube-dl/youtube_dl/extractor/safari.py", line 29, in _real_initialize
    self._login()
  File "/usr/local/bin/youtube-dl/youtube_dl/extractor/safari.py", line 51, in _login
    'https://api.oreilly.com', qs['next'][0])
KeyError: u'next'
Traceback (most recent call last):
  File "/usr/local/bin/youtube-dl/youtube_dl/YoutubeDL.py", line 815, in wrapper
    return func(self, *args, **kwargs)
  File "/usr/local/bin/youtube-dl/youtube_dl/YoutubeDL.py", line 836, in __extract_info
    ie_result = ie.extract(url)
  File "/usr/local/bin/youtube-dl/youtube_dl/extractor/common.py", line 547, in extract
    raise ExtractorError('An extractor error has occurred.', cause=e)
ExtractorError: An extractor error has occurred. (caused by KeyError(u'next',)); please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; type  youtube-dl -U  to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.

```


## Description

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Issue seems to be with some changes on login page of oreilly site. youtube-dl is not able to login and hence can not proceed further.