[CSpan] says the video is not available at this time, but it is actually playable

[ProgrammerAKL]

Checklist

• I'm reporting a broken site support
• I've verified that I'm running youtube-dl version 2020.06.16.1
• 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 issues including closed ones

Verbose log

youtube-dl.exe "https://www.c-span.org/video/?c4890484/user-clip-kai-ping-leung-testimony-house-foreign-affairs-committee" --verbose --list-formats
[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: ['https://www.c-span.org/video/?c4890484/user-clip-kai-ping-leung-testimony-house-foreign-affairs-committee', '--verbose', '--list-formats']
[debug] Encodings: locale cp1252, fs mbcs, out cp437, pref cp1252
[debug] youtube-dl version 2020.06.16.1
[debug] Python version 3.4.4 (CPython) - Windows-10-10.0.18362
[debug] exe versions: none
[debug] Proxy map: {}
[CSpan] c4890484: Downloading webpage
[CSpan] 548896: Downloading JSON metadata
ERROR: CSpan said: Video not available at this time
Traceback (most recent call last):
  File "C:\Users\dst\AppData\Roaming\Build archive\youtube-dl\ytdl-org\tmpspbsbtmq\build\youtube_dl\YoutubeDL.py", line 797, in extract_info
  File "C:\Users\dst\AppData\Roaming\Build archive\youtube-dl\ytdl-org\tmpspbsbtmq\build\youtube_dl\extractor\common.py", line 530, in extract
  File "C:\Users\dst\AppData\Roaming\Build archive\youtube-dl\ytdl-org\tmpspbsbtmq\build\youtube_dl\extractor\cspan.py", line 137, in _real_extract
youtube_dl.utils.ExtractorError: CSpan said: Video not available at this time

youtube-dl.exe "https://www.c-span.org/video/?473530-1/house-foreign-affairs-hearing-chinas-security-law-hong-kong" --verbose --list-formats
[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: ['https://www.c-span.org/video/?473530-1/house-foreign-affairs-hearing-chinas-security-law-hong-kong', '--verbose', '--list-formats']
[debug] Encodings: locale cp1252, fs mbcs, out cp437, pref cp1252
[debug] youtube-dl version 2020.06.16.1
[debug] Python version 3.4.4 (CPython) - Windows-10-10.0.18362
[debug] exe versions: none
[debug] Proxy map: {}
[CSpan] 473530: Downloading webpage
[CSpan] 548896: Downloading JSON metadata
ERROR: CSpan said: Video not available at this time
Traceback (most recent call last):
  File "C:\Users\dst\AppData\Roaming\Build archive\youtube-dl\ytdl-org\tmpspbsbtmq\build\youtube_dl\YoutubeDL.py", line 797, in extract_info
  File "C:\Users\dst\AppData\Roaming\Build archive\youtube-dl\ytdl-org\tmpspbsbtmq\build\youtube_dl\extractor\common.py", line 530, in extract
  File "C:\Users\dst\AppData\Roaming\Build archive\youtube-dl\ytdl-org\tmpspbsbtmq\build\youtube_dl\extractor\cspan.py", line 137, in _real_extract
youtube_dl.utils.ExtractorError: CSpan said: Video not available at this time

Description

These videos are clearly playable in the browser, so I do not know why the extractor thinks they are 'not available at this time'. Presumably, the CSpan extractor needs to be updated.