Can't access tethered server from Android browser. (Time out  or "URL blocked")
Problem may be caused by HTTP Proxy server. Proxies help to manage web traffic on the providers end, but can and probably will disrupt access to local addresses. Proxy options may be available in your network settings, but on many phones these options are hidden. An app such as HTTP Proxy Settings will give access to the hidden settings. Simply clear out the hostname and port for un-proxied access. Make sure to write down original values so changes can be undone.