Sites like isexychat
So you may try to reset the web browser's proxy and then you may try to access again the website to see if it works fine.
Generally the proxy settings are located in the web browser's options page under the section "Advanced" - "LAN Settings".
Some websites may ban the IP address of some popular web proxies, so in this case you just need to change the web proxy with a new one and check if it works.
VPN is the most efficient and robust block bypass method, but it might take you slightly more work initially to set up and may cost some amount of money (for a premium connection).
However if you often need to access the net from behind a blocker and care about your privacy and security it's well worth the effort and the money.
Make sure to enable the option "No proxy" or however untick the option that uses a proxy.