Looks like you have not direct access to the download and where forced to a kind of proxy? And this proxy didn´t allow the download. Hope you are 18 years old and it´s not a setting from your parents to "protect" you or you try your download at work.
If you are on win10 you can try a "tracert www.itch.io" to see the route your request goes.
Use Windows-Key+R and "cmd" to open a console. There you can try "tracert www.itch.io" to test your connection. On Linux equivalent command is traceroute. On android you can browse for traceroutetools.
It could also be a "security" option in your system, looks like you use google chrome? Perhaps you try another browser like firefox? Also check your security envirement, if there is a kind of childprotection or other nonsense to "secure" you.
Damn you can see in child tv fighting and killing each other, but to see some tits you need to be at least 16 and for more sexual content 18. That's moral.
