Hello,
Youtube has many addresses and they change depending on who You ask :-). Here is an example from where I am:
C:\WINDOWS\system32>nslookup www.youtube.com. 8.8.8.8 Server: google-public-dns-a.google.com Address: 8.8.8.8 Non-authoritative answer: Name: youtube-ui.l.google.com Addresses: 2a00:1450:400e:809::200e 172.217.17.46 172.217.17.78 172.217.19.206 172.217.20.110 216.58.212.142 172.217.17.110 172.217.17.142 216.58.211.110 172.217.20.78 216.58.212.206 Aliases: www.youtube.com
From another public DNS:
C:\WINDOWS\system32>nslookup www.youtube.com. 4.2.2.2 Server: b.resolvers.Level3.net Address: 4.2.2.2 Non-authoritative answer: Name: youtube-ui.l.google.com Addresses: 2a00:1450:4005:800::200e 216.58.213.238 172.217.16.78 216.58.213.206 172.217.19.78 Aliases: www.youtube.com
HTH
Thx
Alex