ESP8266WebServer help needed

Other Hardware Home Automation
2

The last 3 lines of code must be inside the {...}.

  server.on("/server", HTTP_GET, [](){
      if (relay1State == 1) {
        relay1StateString = "True";
      }
      else {
        relay1StateString = "False";
      }
      String webString = "Relay 1 " + (relay1StateString);
      Serial.println(webString);
      server.send(200, "text/plain", webString);
    });

Further simplification, optional.

  server.on("/server", HTTP_GET, [](){
      if (relay1State == 1) {
        server.send(200, "text/plain", "Relay 1 True");
      }
      else {
        server.send(200, "text/plain", "Relay 1 False");
      }
    });