404 while retrieving from *.vkcache.com

[initrd]

Checklist

• I'm reporting a broken site support issue
• I've verified that I'm running youtube-dl version 2020.03.24
• 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

$ youtube-dl https://d5g2f6.vkcache.com/secip/0/Hx9ReHEVeaQkdmmAGklTWw/NzMuMTU4LjgwLjE0OQ==/1588237200/hls-vod-s08/flv/api/files/videos/2019/01/04/1546619485mhxm5 --verbose --p
rint-traffic --dump-pages
[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: [u'https://d5g2f6.vkcache.com/secip/0/Hx9ReHEVeaQkdmmAGklTWw/NzMuMTU4LjgwLjE0OQ==/1588237200/hls-vod-s08/flv/api/files/videos/2019/01/04/1546619485mhxm5', u'--verbose', u'--prin
t-traffic', u'--dump-pages']  
[debug] Encodings: locale UTF-8, fs utf-8, out UTF-8, pref UTF-8
[debug] youtube-dl version 2020.03.24
[debug] Python version 2.7.16 (CPython) - Darwin-18.7.0-x86_64-i386-64bit
[debug] exe versions: ffmpeg 4.2.2, ffprobe 4.2.2, rtmpdump 2.4
[debug] Proxy map: {}
[generic] 1546619485mhxm5: Requesting header
send: u'HEAD /secip/0/Hx9ReHEVeaQkdmmAGklTWw/NzMuMTU4LjgwLjE0OQ==/1588237200/hls-vod-s08/flv/api/files/videos/2019/01/04/1546619485mhxm5 HTTP/1.1\r\nAccept-Language: en-us,en;q=0.5\r\nAccept-Encoding: gzip, deflate\r\nConnection: close\r\nAccept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8\r\nUser-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3740.4 Safari/537.36\r\nAccept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7\r\nHost: d5g2f6.vkcache.com\r\n\r\n'
reply: 'HTTP/1.1 404 Not Found\r\n'
header: Server: nginx
header: Date: Thu, 30 Apr 2020 02:06:25 GMT
header: Content-Type: text/html
header: Connection: close
header: strict-transport-security: max-age=10886400; includeSubDomains; preload
header: Access-Control-Allow-Origin: *
header: X-Content-Type-Options: nosniff
WARNING: Could not send HEAD request to https://d5g2f6.vkcache.com/secip/0/Hx9ReHEVeaQkdmmAGklTWw/NzMuMTU4LjgwLjE0OQ==/1588237200/hls-vod-s08/flv/api/files/videos/2019/01/04/1546619485mhxm5: HTTP Error 404: Not Found
[generic] 1546619485mhxm5: Downloading webpage
send: u'GET /secip/0/Hx9ReHEVeaQkdmmAGklTWw/NzMuMTU4LjgwLjE0OQ==/1588237200/hls-vod-s08/flv/api/files/videos/2019/01/04/1546619485mhxm5 HTTP/1.1\r\nAccept-Language: en-us,en;q=0.5\r\nAccept-Encoding: *\r\nConnection: close\r\nAccept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8\r\nUser-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3740.4 Safari/537.36\r\nAccept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7\r\nHost: d5g2f6.vkcache.com\r\n\r\n'
reply: 'HTTP/1.1 404 Not Found\r\n'
header: Server: nginx
header: Date: Thu, 30 Apr 2020 02:06:26 GMT
header: Content-Type: text/html
header: Transfer-Encoding: chunked
header: Connection: close
header: strict-transport-security: max-age=10886400; includeSubDomains; preload
header: Access-Control-Allow-Origin: *
header: X-Content-Type-Options: nosniff

Description

youtube-dl fails while retrieving the header for a webpage. However I can run curl to retrieve without any trouble:

$ curl -v -I 'https://d5g2f6.vkcache.com/secip/0/Hx9ReHEVeaQkdmmAGklTWw/NzMuMTU4LjgwLjE0OQ==/1588237200/hls-vod-s08/flv/api/files/videos/2019/01/04/1546619485mhxm5'
*   Trying 50.7.230.18...
* TCP_NODELAY set
* Connected to d5g2f6.vkcache.com (50.7.230.18) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* Cipher selection: ALL:!EXPORT:!EXPORT40:!EXPORT56:!aNULL:!LOW:!RC4:@STRENGTH
* successfully set certificate verify locations:
*   CAfile: /etc/ssl/cert.pem
  CApath: none
* TLSv1.2 (OUT), TLS handshake, Client hello (1):
} [224 bytes data]
* TLSv1.2 (IN), TLS handshake, Server hello (2):
{ [108 bytes data]
* TLSv1.2 (IN), TLS handshake, Certificate (11):
{ [4510 bytes data]
* TLSv1.2 (IN), TLS handshake, Server key exchange (12):
{ [300 bytes data]
* TLSv1.2 (IN), TLS handshake, Server finished (14):
{ [4 bytes data]
* TLSv1.2 (OUT), TLS handshake, Client key exchange (16):
} [37 bytes data]
* TLSv1.2 (OUT), TLS change cipher, Client hello (1):
} [1 bytes data]
* TLSv1.2 (OUT), TLS handshake, Finished (20):
} [16 bytes data]
* TLSv1.2 (IN), TLS change cipher, Client hello (1):
{ [1 bytes data]
* TLSv1.2 (IN), TLS handshake, Finished (20):
{ [16 bytes data]
* SSL connection using TLSv1.2 / ECDHE-RSA-AES128-GCM-SHA256
* ALPN, server accepted to use http/1.1
* Server certificate:
*  subject: OU=Domain Control Validated; OU=EssentialSSL Wildcard; CN=*.vkcache.com
*  start date: May 12 00:00:00 2019 GMT
*  expire date: May 11 23:59:59 2020 GMT
*  subjectAltName: host "d5g2f6.vkcache.com" matched cert's "*.vkcache.com"
*  issuer: C=GB; ST=Greater Manchester; L=Salford; O=Sectigo Limited; CN=Sectigo RSA Domain Validation Secure Server CA
*  SSL certificate verify ok.
> HEAD /secip/0/Hx9ReHEVeaQkdmmAGklTWw/NzMuMTU4LjgwLjE0OQ==/1588237200/hls-vod-s08/flv/api/files/videos/2019/01/04/1546619485mhxm5 HTTP/1.1
> Host: d5g2f6.vkcache.com
> User-Agent: curl/7.54.0
> Accept: */*
> 
< HTTP/1.1 200 OK
< Server: nginx
< Date: Thu, 30 Apr 2020 02:19:30 GMT
< Content-Type: application/octet-stream-m3u8
< Connection: keep-alive
< Expires: Fri, 30 Apr 2021 02:19:30 GMT
< Cache-Control: max-age=31536000
< strict-transport-security: max-age=10886400; includeSubDomains; preload
< Access-Control-Allow-Origin: *
< X-Content-Type-Options: nosniff
< X-Cache-Status: HIT
< Cache-Control: public
< 
* Connection #0 to host d5g2f6.vkcache.com left intact
HTTP/1.1 200 OK
Server: nginx
Date: Thu, 30 Apr 2020 02:19:30 GMT
Content-Type: application/octet-stream-m3u8
Connection: keep-alive
Expires: Fri, 30 Apr 2021 02:19:30 GMT
Cache-Control: max-age=31536000
strict-transport-security: max-age=10886400; includeSubDomains; preload
Access-Control-Allow-Origin: *
X-Content-Type-Options: nosniff
X-Cache-Status: HIT
Cache-Control: public

[dstftw]

Same 404 for me in browser.

[initrd]

Was able to get this to work by adding --add-header Accept:"*". Turns out the webserver would return a 404 with the default Accept header from the browser (and youtube-dl).