I've Arduino Uno and ESP8266, wanted to connect and control LED from WebServer, I made connection referring This Image , loaded arduino with WifiWebServer code and applied my router's credentials there

char ssid[] = "Router SSID"; // your network SSID (name) char pass[] = "Router's WPA Password";

I'm getting "Wifi Shield not present" message from Serial Monitor, even I tried by giving external 3.3v power supply to esp8266 module, but no change. What am I missing here? Can someone help me to fix this issue?