Some sites can not be found when you’re using the free WIFI. It can be blocked (eg, gutteruncensored.com) or simple because the proxy server is not resolving the domain name. The following are the common error message you will see:
Requested URL not found
Add 208.67.222.222 and 208.67.220.220 as your DNS under the TCP/IP setting can solve the problem immediately. The pair of IP addresses are provided by OpenDNS, a far more reliable and free DNS server.