HTTP Error 404 but in browser page is valid

[quazal78]

Checklist

Version:
I updated using this: sudo curl -L https://yt-dl.org/downloads/latest/youtube-dl -o /usr/local/bin/youtube-dl
and my current version is 2020.05.03 not 2020.06.06 as mentioned. I am on ubuntu 16.04

Also tried adding -u PRIVATE

• [ x] I'm reporting a broken site support
• [ N] I've verified that I'm running youtube-dl version 2020.06.06
• [ 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 issues including closed ones

Verbose log

Error:
WARNING: Could not send HEAD request to https://learn.unity.com/tutorial/custom-render-passes-with-lwrp: HTTP Error 404: Not Found
[generic] custom-render-passes-with-lwrp: Downloading webpage
WARNING: Falling back on generic information extractor.
[generic] custom-render-passes-with-lwrp: Extracting information
ERROR: Unsupported URL: https://learn.unity.com/tutorial/custom-render-passes-with-lwrp
Traceback (most recent call last):
  File "/usr/local/bin/youtube-dl/youtube_dl/YoutubeDL.py", line 797, in extract_info
    ie_result = ie.extract(url)
  File "/usr/local/bin/youtube-dl/youtube_dl/extractor/common.py", line 530, in extract
    ie_result = self._real_extract(url)
  File "/usr/local/bin/youtube-dl/youtube_dl/extractor/generic.py", line 3370, in _real_extract
    raise UnsupportedError(url)
youtube_dl.utils.UnsupportedError: Unsupported URL: https://learn.unity.com/tutorial/custom-render-passes-with-lwrp

Description

According to https://ytdl-org.github.io/youtube-dl/supportedsites.html, unity is supported.
I tried the following:
youtube-dl --username --password --verbose https://learn.unity.com/tutorial/custom-render-passes-with-lwrp

Also tried
youtube-dl --cookies ./unity.txt --verbose "https://learn.unity.com/tutorial/custom-render-passes-with-lwrp"

Also tried adding -u PRIVATE