[YouTube] Unable to Login With Error 400: Bad Request

[JeffStevens8418]

Checklist

• I'm reporting a broken site support issue
• I've verified that I'm running youtube-dl version 2020.01.24
• I've checked that all provided URLs are alive and playable in a browser
• I've checked that all URLs and arguments with special characters are properly quoted or escaped
• I've searched the bugtracker for similar bug reports including closed ones
• I've read bugs section in FAQ

Verbose log

[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: ['-v', '-u', 'PRIVATE', '-p', 'PRIVATE', '-i', '-o', '%(title)s.%(ext)s', '-f', 'bestaudio', 'https://www.youtube.com/playlist?list=PLvp4VXyzLxQypO-Ug3tMOLKx19QAdkH8K']
[debug] Encodings: locale cp1252, fs mbcs, out cp437, pref cp1252
[debug] youtube-dl version 2020.01.24
[debug] Python version 3.4.4 (CPython) - Windows-7-6.1.7601-SP1
[debug] exe versions: ffmpeg git-2020-01-24-e931119
[debug] Proxy map: {}
[youtube:playlist] Downloading login page
[youtube:playlist] Looking up account info
[youtube:playlist] Logging in
WARNING: Unable to log in: HTTP Error 400: Bad Request
[youtube:playlist] PLvp4VXyzLxQypO-Ug3tMOLKx19QAdkH8K: Downloading webpage
ERROR: This playlist is private, use --username or --netrc to access it.
Traceback (most recent call last):
  File "C:\Users\dst\AppData\Roaming\Build archive\youtube-dl\ytdl-org\tmpw0w300z1\build\youtube_dl\YoutubeDL.py", line 796, in extract_info
  File "C:\Users\dst\AppData\Roaming\Build archive\youtube-dl\ytdl-org\tmpw0w300z1\build\youtube_dl\extractor\common.py", line 530, in extract
  File "C:\Users\dst\AppData\Roaming\Build archive\youtube-dl\ytdl-org\tmpw0w300z1\build\youtube_dl\extractor\youtube.py", line 2815, in _real_extract
  File "C:\Users\dst\AppData\Roaming\Build archive\youtube-dl\ytdl-org\tmpw0w300z1\build\youtube_dl\extractor\youtube.py", line 2738, in _extract_playlist
youtube_dl.utils.ExtractorError: This playlist is private, use --username or --netrc to access it.

Description

A couple days ago, I wanted to download some audio from a private YouTube playlist on my account. I went to use my usual commands and kept on getting 'Unable to log in: HTTP Error 400: Bad Request.' Today, I tried again to no prevail.

I believe that YouTube changed something on their end recently and that is why I am getting this error. I am drawn to this conclusion as I started getting the error out of the blue without updating YouTube-DL at all. I was also able to replicate this same error on other Windows computers as well.

I know this issue has already been addressed in other reports, but just wanted to add some other details that might help get this issue resolved.