Please do not post screenshots if you talk about plain text.
This makes it for example super-hard to copy the text that you screenshotted.
I tried to download the first URL from your screenshot it complained about and it worked perfectly fine.
So I’d guess it was either a temporary issue if it works for you now too.
If it still does not work for you, I’d suspect some anti-virus, firewall, or not-configured proxy that prevents you to download those files.