Why can't access these website?
Your isp was blocked this or any illegal website address in Domain Name System.So you can't access the website.
There are 3 Safe ways Available for Access Blocked Websites...
Vpn is called Virtual Private Network..it was Replace different Ip to your ip.
Example: You are India.you will connect Us server Vpn.Your ip and isp is always changing for you connecting the Vpn.
Free vpn provider: Vpnbook
proxy server is a server that acts as an intermediary for requests from clients seeking resources from other servers.They can not fully secure.it only break your Internet Service Provider.
Free proxy : https://www.proxysite.com/,https://www.hidemyass.com/en-us/proxy,https://kproxy.com/
Tor is multiple lawyer of Encrypted Private Network.They will connecting Secure.You can Access Anything this world like Onion services and Blocked Internet services.
Tor (anonymity network) Tor is free software for enabling anonymous communication.
Download Tor Browser: https://www.torproject.org/download/