Repository: yt-dlp
Issue: `--ap-mso Comcast_SSO` broken
Labels: account-needed,site-bug,patch-available,can-share-account

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## Checklist

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- First of, make sure you are using the latest version of yt-dlp. Run `yt-dlp --version` and ensure your version is 2021.07.07. If it's not, see https://github.com/yt-dlp/yt-dlp 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 Issues with outdated version will be REJECTED.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.
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- [x] I'm reporting a broken site support issue
- [x] I've verified that I'm running yt-dlp version **2021.07.07**
- [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 yt-dlp that clearly demonstrates the problem.
Add the `-v` flag to your command line you run yt-dlp with (`yt-dlp -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_jenozKc']
 [debug] Encodings: locale cp1251, fs mbcs, out cp866, pref cp1251
 [debug] yt-dlp version 2021.07.07
 [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>
-->

```
[debug] Command-line config: ['--ap-mso', 'Comcast_SSO', '--ap-username', 'PRIVATE', '--ap-password', 'PRIVATE', '--all-subs', '--convert-subs', 'srt', '--verbose', 'https://abc.com/shows/when-nature-calls/episode-guide/season-01/03-dastardly-death-gunk-stuff']
[debug] Encodings: locale cp1252, fs utf-8, out utf-8, pref cp1252
[debug] yt-dlp version 2021.07.07 (exe)
[debug] Python version 3.8.10 (CPython 64bit) - Windows-10-10.0.19043-SP0
[debug] exe versions: ffmpeg 2021-07-14-git-ca56299fb3-full_build-www.gyan.dev, ffprobe 2021-07-14-git-ca56299fb3-full_build-www.gyan.dev
[debug] Proxy map: {}
[debug] [Go] Extracting URL: https://abc.com/shows/when-nature-calls/episode-guide/season-01/03-dastardly-death-gunk-stuff
ERROR: Unable to download webpage: HTTP Error 401: Unauthorized (caused by <HTTPError 401: 'Unauthorized'>); please report this issue on  https://github.com/yt-dlp/yt-dlp . Make sure you are using the latest version; see  https://github.com/yt-dlp/yt-dlp  on how to update. Be sure to call yt-dlp with the --verbose flag and include its complete output.
  File "yt_dlp\extractor\common.py", line 680, in _request_webpage
  File "yt_dlp\YoutubeDL.py", line 3086, in urlopen
  File "urllib\request.py", line 531, in open
  File "urllib\request.py", line 640, in http_response
  File "urllib\request.py", line 569, in error
  File "urllib\request.py", line 502, in _call_chain
  File "urllib\request.py", line 649, in http_error_default



```
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## Description

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Cannot get --ap-mso Comcast_SSO to work, no matter what I do. I have a legit login/password. I am off-network. I can watch the videos online using MS-Edge and Adobe Pass seems to work perfectly there.  I have tried using --ap-mso, I have tried using the cookies file, a combination of both, but nothing seems to work.  Please assist.