Send responses to GET requests - ESP8266 as webserver
you will have to reply with a full HTTP header. Something like:

HTTP/1.1 200 OK&lt\r>&lt\n>
Content-Length: 0&lt\r>&lt\n>  
&lt\r>&lt\n>

The TSP8266 doesn't seem to support HTTP, so you'll have to either send this response via UART for every connection or you write a firmware for the ESP8266 that has a (partly) functioning webserver.