ERROR: iaHxBCTP6-g: "token" parameter not in video info for unknown reason

[yongbok1102]

I've written a Python source code like this :

#coding=utf-8
import cv2
import pafy

#YouTube 동영상 url (제목 : [동심파괴 더빙] 설탕이 아니야!)
url = 'https://www.youtube.com/watch?v=iaHxBCTP6-g'

video = pafy.new(url) #YouTube url로부터 pafy.backend_youdube_dl.YtdlPafy 클래스 객체 생
print('title=', video.title)
print('video rating=',video.rating)
print('video durarion=',video.duration)

best = video.getbest(preftype='webm') #비디오 파일양식 webm의 최적의 pafy.backend_youtube_dl.YtdlStream 클래스 객체 생성
print('best resolution', best.resolution)

cap = cv2.VideoCapture(best.url)
while True :
retval, frame = cap.read()

if not retval : 
    break

cv2.imshow('frame',frame)

gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
edges = cv2.Canny(gray,100,200) #에지 검출
cv2.imshow('edges',edges)

key = cv2.waitKey(25)

if key == 27 : 
    break

cv2.destroyAllWindows()

But when I ran this source code, the error occured. The message is written below.

ERROR: iaHxBCTP6-g: "token" parameter not in video info for unknown reason; please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; see https://yt-dl.org/update on how to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.
Traceback (most recent call last):
File "D:\Python37\lib\site-packages\youtube_dl\YoutubeDL.py", line 792, in extract_info
ie_result = ie.extract(url)
File "D:\Python37\lib\site-packages\youtube_dl\extractor\common.py", line 507, in extract
ie_result = self._real_extract(url)
File "D:\Python37\lib\site-packages\youtube_dl\extractor\youtube.py", line 1654, in _real_extract
video_id=video_id)
youtube_dl.utils.ExtractorError: iaHxBCTP6-g: "token" parameter not in video info for unknown reason; please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; see https://yt-dl.org/update on how to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "D:\Python37\lib\site-packages\pafy\backend_youtube_dl.py", line 38, in _fetch_basic
self._ydl_info = ydl.extract_info(self.videoid, download=False)
File "D:\Python37\lib\site-packages\youtube_dl\YoutubeDL.py", line 815, in extract_info
self.report_error(compat_str(e), e.format_traceback())
File "D:\Python37\lib\site-packages\youtube_dl\YoutubeDL.py", line 620, in report_error
self.trouble(error_message, tb)
File "D:\Python37\lib\site-packages\youtube_dl\YoutubeDL.py", line 590, in trouble
raise DownloadError(message, exc_info)
youtube_dl.utils.DownloadError: ERROR: iaHxBCTP6-g: "token" parameter not in video info for unknown reason; please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; see https://yt-dl.org/update on how to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "D:\Devel\python_opencv\ch002\0209.py", line 8, in
video = pafy.new(url) #YouTube url로부터 pafy.backend_youdube_dl.YtdlPafy 클래스 객체 생
File "D:\Python37\lib\site-packages\pafy\pafy.py", line 124, in new
return Pafy(url, basic, gdata, size, callback, ydl_opts)
File "D:\Python37\lib\site-packages\pafy\backend_youtube_dl.py", line 29, in init
super(YtdlPafy, self).init(*args, **kwargs)
File "D:\Python37\lib\site-packages\pafy\backend_shared.py", line 96, in init
self._fetch_basic()
File "D:\Python37\lib\site-packages\pafy\backend_youtube_dl.py", line 41, in _fetch_basic
raise IOError(str(e).replace('YouTube said', 'Youtube says'))
OSError: ERROR: iaHxBCTP6-g: "token" parameter not in video info for unknown reason; please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; see https://yt-dl.org/update on how to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.

I wonder the reason the error occured and want it to be solved.