user46167: I can successfully send a GET request with the ESP8266HTTPClient library in the first sketch. However the exactly same code won't work when used in the second sketch, which is more complex and uses other libraries too. I'm not sure why, maybe a conflict between libraries?
Sketch 1 (working)
#define DEBUG

#ifdef DEBUG
  #define SB(...) Serial.begin(__VA_ARGS__)
  #define SP(...) Serial.print(__VA_ARGS__)
  #define SPL(...) Serial.println(__VA_ARGS__)
#else
  #define SB(...) 
  #define SP(...)
  #define SPL(...)
#endif

#include <ESP8266WiFi.h>
#include <WiFiClient.h>
#include <ESP8266WebServer.h>
#include <ESP8266HTTPClient.h>
const char* ssid = "TALKTALK-17409C";
const char* password = "HPHRKJYX";

void setup() {

   SB(115200);
  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {  
    delay(500);
    SPL("Waiting to connect…");
  }

  if (WiFi.status() == WL_CONNECTED) {
    HTTPClient http;
    http.begin("http://francescosoave.com/blind/getTime.php?pw=ciao");
    int httpCode = http.GET();
    SP("HTTP: ");
    SPL(httpCode);
    if(httpCode > 0){
      String payload = http.getString();
      SP("PAYLOAD: ");
      SPL(payload);
    }

    http.end();
  }
}

void loop() {}

Sketch 1 response in the serial monitor (Tools -> Debug port -> Serial // Tools -> Debug Level -> HTTP_CLIENT)
SDK:2.2.1(cfd48f3)/Core:2.4.1/lwIP:2.0.3(STABLE-2_0_3_RELEASE/glue:arduino-2.4.1)
scandone
scandone
state: 0 -> 2 (b0)
state: 2 -> 3 (0)
state: 3 -> 5 (10)
add 0
aid 3
cnt 
Waiting to connect…

connected with TALKTALK-17409C, channel 10
dhcp client start...
Waiting to connect…
ip:192.168.1.4,mask:255.255.255.0,gw:192.168.1.1
Waiting to connect…
[HTTP-Client][begin] url: http://francescosoave.com/blind/getTime.php?pw=ciao
[HTTP-Client][begin] host: francescosoave.com port: 80 url: /blind/getTime.php?pw=ciao
[HTTP-Client] connected to francescosoave.com:80
[HTTP-Client] sending request header
-----
GET /blind/getTime.php?pw=ciao HTTP/1.1
Host: francescosoave.com
User-Agent: ESP8266HTTPClient
Connection: close
Accept-Encoding: identity;q=1,chunked;q=0.1,*;q=0

-----
[HTTP-Client][handleHeaderResponse] RX: 'HTTP/1.1 200 OK'
[HTTP-Client][handleHeaderResponse] RX: 'Server: nginx'
[HTTP-Client][handleHeaderResponse] RX: 'Date: Wed, 08 Aug 2018 21:24:46 GMT'
[HTTP-Client][handleHeaderResponse] RX: 'Content-Type: text/html; charset=UTF-8'
[HTTP-Client][handleHeaderResponse] RX: 'Transfer-Encoding: chunked'
[HTTP-Client][handleHeaderResponse] RX: 'Connection: close'
[HTTP-Client][handleHeaderResponse] RX: 'Vary: Accept-Encoding'
[HTTP-Client][handleHeaderResponse] RX: 'X-Powered-By: PHP/5.6.32'
[HTTP-Client][handleHeaderResponse] RX: 'Vary: Accept-Encoding'
[HTTP-Client][handleHeaderResponse] RX: 'Access-Control-Allow-Origin: *'
[HTTP-Client][handleHeaderResponse] RX: ''
[HTTP-Client][handleHeaderResponse] code: 200
[HTTP-Client][handleHeaderResponse] Transfer-Encoding: chunked
HTTP: 200
[HTTP-Client] read chunk len: 11
[HTTP-Client][writeToStreamDataBlock] connection closed or file end (written: 11).
[HTTP-Client] read chunk len: 0
[HTTP-Client][end] still data in buffer (2), clean up.
[HTTP-Client][end] tcp stop
PAYLOAD: TIME: 22:24
[HTTP-Client][end] tcp is closed
pm open,type:2 0

Sketch 2 (not working)
#define DEBUG

#ifdef DEBUG
  #define SB(...) Serial.begin(__VA_ARGS__)
  #define SP(...) Serial.print(__VA_ARGS__)
  #define SPL(...) Serial.println(__VA_ARGS__)
#else
  #define SB(...) 
  #define SP(...)
  #define SPL(...)
#endif

#include <ESP8266WiFi.h>
#include <WiFiClient.h>
#include <ESP8266WebServer.h>
#include <ESP8266HTTPClient.h>

const char* ssid = "TALKTALK-17409C";
const char* password = "HPHRKJYX";

ESP8266WebServer server(80);   //instantiate server at port 80 (http port)
IPAddress ip(192, 168, 1, 7);
IPAddress gateway(192, 168, 1, 1);
IPAddress subnet(255, 255, 255, 0);

String pageFinal = "";
byte curPos;
boolean timerState = true; //true = on, false = off
//int[] curTime = {0, 0}; // {hour, minutes

// HTML PAGES
String page1="<!DOCTYPE html>"
"<html>"
"<head>"
"<meta charset='utf-8'/>"
"<meta name='viewport' content='width=device-width, initial-scale=1'>"
"<meta http-equiv='Content-Type' content='text/html;charset=UTF-8' />"
"<link rel='stylesheet' href='https://stackpath.bootstrapcdn.com/bootstrap/4.1.2/css/bootstrap.min.css' integrity='sha384-Smlep5jCw/wG7hdkwQ/Z5nLIefveQRIY9nfy6xoR1uRYBtpZgI6339F5dgvm/e9B' crossorigin='anonymous'>"
"<link rel='stylesheet' type='text/css' href='http://www.francescosoave.com/blind/style.css'>"
"<script src='https://ajax.aspnetcdn.com/ajax/jQuery/jquery-3.3.1.min.js' type='text/javascript'></script>"
"<script src='https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js'></script>"
"</head>"
"<body>"
"<div class='container'>"
"<div class='row'>"
"<table class='table' id='radioForm'>"
"<thead>"
"<tr><th>Fran's Blind</th></tr>"
"</thead>"
"<tbody>"
"<tr><td align='center'>"
"<form action='/' method='get' id='manualForm'>"
"<input id='1' type='submit' class='btn btn-primary' name='manualBtn' value='1' />"
"</td></tr>"
"<tr><td align='center'>"
"<input id='2' type='submit' class='btn btn-primary' name='manualBtn' value='2' />"
"</td></tr>"
"<tr><td align='center'>"
"<input id='3' type='submit' class='btn btn-primary' name='manualBtn' value='3' />"
"</td></tr>"
"<tr><td align='center'>"
"<input id='4' type='submit' class='btn btn-primary' name='manualBtn' value='4' />"
"</td></tr>"
"<tr><td align='center'>"
"<input id='5' type='submit' class='btn btn-primary' name='manualBtn' value='5' />"
"</td></tr>"
"<tr><td align='center'>"
"<input id='6' type='submit' class='btn btn-primary' name='manualBtn' value='6' />"
"</td></tr>"
"<tr><td align='center'>"
"<input id='7' type='submit' class='btn btn-primary' name='manualBtn' value='7' />"
"</form>"
"</td></tr>"
"<tr><td align='center'><form action='/' method='get'>"
"<input id='timer' name='timerBtn' value='' class='' type='submit'></form><p>Timer is <span id='timerMsg'></span></p>"
"</td></tr>"
"</tbody>"
"</table>"
"</div>"
"</div>"
"</body>"
"<script>"
"$( document ).ready(function() {"
"setInterval(function(){"
"$('#timerMsg').fadeOut(function () {"
"$(this).fadeIn();"
"});"
"} ,1000);";

// page2 / page2_5 change timer button
// page 3/ page3_5 change current position button
String page2 = "$('#timer').attr({'class': 'btn btn-danger', value: 'TURN OFF'});$('#timerMsg').html('on');});";
String page2_5 = "$('#timer').attr({'class': 'btn btn-success', value: 'TURN ON'});$('#timerMsg').html('off');});";
String page3 = "$('#";
String page3_5 = "').attr({'class': 'btn btn-warning'});";
String page4 = "</script></html>";

void setup(void){

  WiFi.config(ip, gateway, subnet); 
  delay(1000);
  SB(115200);
  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {  
    delay(500);
    SPL("Waiting to connect…");
  }

  SP("IP address: ");
  SPL(WiFi.localIP());

  //here's the same GET request as in Sketch 1 but here it doesn't work
if (WiFi.status() == WL_CONNECTED) {
    HTTPClient http;
    http.begin("http://francescosoave.com/blind/getTime.php?pw=ciao");
    int httpCode = http.GET();
   SP("HTTP: ");
   SPL(httpCode);
    if(httpCode > 0){
      String payload = http.getString();
      SP("PAYLOAD: ");
      SPL(payload);
    }

    http.end();
  }

  server.on("/", control);  
  server.begin();
  SPL("Server listening");
}

int  i = 0;

void loop(void){
  server.handleClient();
}

void control(){

  if(server.args() > 0){ //there is something to change
    if(server.argName(0) == "timerBtn"){
      timerState = !timerState; //change timer
    }else if(server.argName(0) == "manualBtn"){
      curPos = server.arg(0).toInt(); //change current (manual)
    }
  }

  //build the page
  if(timerState)
    pageFinal = page1 + page2;
  else
    pageFinal = page1 + page2_5;

  pageFinal += page3 + curPos + page3_5 + page4;        
  server.send(200, "text/html", pageFinal);
}

Sketch 2 response in the serial monitor (Tools -> Debug port -> Serial // Tools -> Debug Level -> HTTP_CLIENT)
SDK:2.2.1(cfd48f3)/Core:2.4.1/lwIP:2.0.3(STABLE-2_0_3_RELEASE/glue:arduino-2.4.1)
scandone
Waiting to connectâ€¦
IP address: 192.168.1.7
[HTTP-Client][begin] url: http://francescosoave.com/blind/getTime.php?pw=ciao
[HTTP-Client][begin] host: francescosoave.com port: 80 url: /blind/getTime.php?pw=ciao
[HTTP-Client] failed connect to francescosoave.com:80
[HTTP-Client][returnError] error(-1): connection refused
HTTP: -1
[HTTP-Client][end] tcp is closed
Server listening
pm open,type:2 0

edit: the issue was in the Wifi.config() line. It should be WiFi.config(ip, gateway, subnet, gateway); 

user37622: If you want to configure a static IP address, make sure it is unique in you LAN and outside the range managed by the DHCP server.
EDIT:
the WiFi.config() function doesn't assign the gateway address as DNS address. add 4th parameter with DNS server address.
WiFi.config(ip, gateway, subnet, gateway);


46167: <p>I can successfully send a GET request with the ESP8266HTTPClient library in the first sketch. However the exactly same code won't work when used in the second sketch, which is more complex and uses other libraries too. I'm not sure why, maybe a conflict between libraries?</p>

<p>Sketch 1 (working)</p>

<pre><code>#define DEBUG

#ifdef DEBUG
  #define SB(...) Serial.begin(__VA_ARGS__)
  #define SP(...) Serial.print(__VA_ARGS__)
  #define SPL(...) Serial.println(__VA_ARGS__)
#else
  #define SB(...) 
  #define SP(...)
  #define SPL(...)
#endif

#include &lt;ESP8266WiFi.h&gt;
#include &lt;WiFiClient.h&gt;
#include &lt;ESP8266WebServer.h&gt;
#include &lt;ESP8266HTTPClient.h&gt;
const char* ssid = "TALKTALK-17409C";
const char* password = "HPHRKJYX";

void setup() {

   SB(115200);
  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {  
    delay(500);
    SPL("Waiting to connect…");
  }

  if (WiFi.status() == WL_CONNECTED) {
    HTTPClient http;
    http.begin("http://francescosoave.com/blind/getTime.php?pw=ciao");
    int httpCode = http.GET();
    SP("HTTP: ");
    SPL(httpCode);
    if(httpCode &gt; 0){
      String payload = http.getString();
      SP("PAYLOAD: ");
      SPL(payload);
    }

    http.end();
  }
}

void loop() {}
</code></pre>

<p>Sketch 1 response in the serial monitor (Tools -> Debug port -> Serial // Tools -> Debug Level -> HTTP_CLIENT)</p>

<pre><code>SDK:2.2.1(cfd48f3)/Core:2.4.1/lwIP:2.0.3(STABLE-2_0_3_RELEASE/glue:arduino-2.4.1)
scandone
scandone
state: 0 -&gt; 2 (b0)
state: 2 -&gt; 3 (0)
state: 3 -&gt; 5 (10)
add 0
aid 3
cnt 
Waiting to connect…

connected with TALKTALK-17409C, channel 10
dhcp client start...
Waiting to connect…
ip:192.168.1.4,mask:255.255.255.0,gw:192.168.1.1
Waiting to connect…
[HTTP-Client][begin] url: http://francescosoave.com/blind/getTime.php?pw=ciao
[HTTP-Client][begin] host: francescosoave.com port: 80 url: /blind/getTime.php?pw=ciao
[HTTP-Client] connected to francescosoave.com:80
[HTTP-Client] sending request header
-----
GET /blind/getTime.php?pw=ciao HTTP/1.1
Host: francescosoave.com
User-Agent: ESP8266HTTPClient
Connection: close
Accept-Encoding: identity;q=1,chunked;q=0.1,*;q=0

-----
[HTTP-Client][handleHeaderResponse] RX: 'HTTP/1.1 200 OK'
[HTTP-Client][handleHeaderResponse] RX: 'Server: nginx'
[HTTP-Client][handleHeaderResponse] RX: 'Date: Wed, 08 Aug 2018 21:24:46 GMT'
[HTTP-Client][handleHeaderResponse] RX: 'Content-Type: text/html; charset=UTF-8'
[HTTP-Client][handleHeaderResponse] RX: 'Transfer-Encoding: chunked'
[HTTP-Client][handleHeaderResponse] RX: 'Connection: close'
[HTTP-Client][handleHeaderResponse] RX: 'Vary: Accept-Encoding'
[HTTP-Client][handleHeaderResponse] RX: 'X-Powered-By: PHP/5.6.32'
[HTTP-Client][handleHeaderResponse] RX: 'Vary: Accept-Encoding'
[HTTP-Client][handleHeaderResponse] RX: 'Access-Control-Allow-Origin: *'
[HTTP-Client][handleHeaderResponse] RX: ''
[HTTP-Client][handleHeaderResponse] code: 200
[HTTP-Client][handleHeaderResponse] Transfer-Encoding: chunked
HTTP: 200
[HTTP-Client] read chunk len: 11
[HTTP-Client][writeToStreamDataBlock] connection closed or file end (written: 11).
[HTTP-Client] read chunk len: 0
[HTTP-Client][end] still data in buffer (2), clean up.
[HTTP-Client][end] tcp stop
PAYLOAD: TIME: 22:24
[HTTP-Client][end] tcp is closed
pm open,type:2 0
</code></pre>

<p>Sketch 2 (not working)</p>

<pre><code>#define DEBUG

#ifdef DEBUG
  #define SB(...) Serial.begin(__VA_ARGS__)
  #define SP(...) Serial.print(__VA_ARGS__)
  #define SPL(...) Serial.println(__VA_ARGS__)
#else
  #define SB(...) 
  #define SP(...)
  #define SPL(...)
#endif

#include &lt;ESP8266WiFi.h&gt;
#include &lt;WiFiClient.h&gt;
#include &lt;ESP8266WebServer.h&gt;
#include &lt;ESP8266HTTPClient.h&gt;

const char* ssid = "TALKTALK-17409C";
const char* password = "HPHRKJYX";

ESP8266WebServer server(80);   //instantiate server at port 80 (http port)
IPAddress ip(192, 168, 1, 7);
IPAddress gateway(192, 168, 1, 1);
IPAddress subnet(255, 255, 255, 0);

String pageFinal = "";
byte curPos;
boolean timerState = true; //true = on, false = off
//int[] curTime = {0, 0}; // {hour, minutes

// HTML PAGES
String page1="&lt;!DOCTYPE html&gt;"
"&lt;html&gt;"
"&lt;head&gt;"
"&lt;meta charset='utf-8'/&gt;"
"&lt;meta name='viewport' content='width=device-width, initial-scale=1'&gt;"
"&lt;meta http-equiv='Content-Type' content='text/html;charset=UTF-8' /&gt;"
"&lt;link rel='stylesheet' href='https://stackpath.bootstrapcdn.com/bootstrap/4.1.2/css/bootstrap.min.css' integrity='sha384-Smlep5jCw/wG7hdkwQ/Z5nLIefveQRIY9nfy6xoR1uRYBtpZgI6339F5dgvm/e9B' crossorigin='anonymous'&gt;"
"&lt;link rel='stylesheet' type='text/css' href='http://www.francescosoave.com/blind/style.css'&gt;"
"&lt;script src='https://ajax.aspnetcdn.com/ajax/jQuery/jquery-3.3.1.min.js' type='text/javascript'&gt;&lt;/script&gt;"
"&lt;script src='https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js'&gt;&lt;/script&gt;"
"&lt;/head&gt;"
"&lt;body&gt;"
"&lt;div class='container'&gt;"
"&lt;div class='row'&gt;"
"&lt;table class='table' id='radioForm'&gt;"
"&lt;thead&gt;"
"&lt;tr&gt;&lt;th&gt;Fran's Blind&lt;/th&gt;&lt;/tr&gt;"
"&lt;/thead&gt;"
"&lt;tbody&gt;"
"&lt;tr&gt;&lt;td align='center'&gt;"
"&lt;form action='/' method='get' id='manualForm'&gt;"
"&lt;input id='1' type='submit' class='btn btn-primary' name='manualBtn' value='1' /&gt;"
"&lt;/td&gt;&lt;/tr&gt;"
"&lt;tr&gt;&lt;td align='center'&gt;"
"&lt;input id='2' type='submit' class='btn btn-primary' name='manualBtn' value='2' /&gt;"
"&lt;/td&gt;&lt;/tr&gt;"
"&lt;tr&gt;&lt;td align='center'&gt;"
"&lt;input id='3' type='submit' class='btn btn-primary' name='manualBtn' value='3' /&gt;"
"&lt;/td&gt;&lt;/tr&gt;"
"&lt;tr&gt;&lt;td align='center'&gt;"
"&lt;input id='4' type='submit' class='btn btn-primary' name='manualBtn' value='4' /&gt;"
"&lt;/td&gt;&lt;/tr&gt;"
"&lt;tr&gt;&lt;td align='center'&gt;"
"&lt;input id='5' type='submit' class='btn btn-primary' name='manualBtn' value='5' /&gt;"
"&lt;/td&gt;&lt;/tr&gt;"
"&lt;tr&gt;&lt;td align='center'&gt;"
"&lt;input id='6' type='submit' class='btn btn-primary' name='manualBtn' value='6' /&gt;"
"&lt;/td&gt;&lt;/tr&gt;"
"&lt;tr&gt;&lt;td align='center'&gt;"
"&lt;input id='7' type='submit' class='btn btn-primary' name='manualBtn' value='7' /&gt;"
"&lt;/form&gt;"
"&lt;/td&gt;&lt;/tr&gt;"
"&lt;tr&gt;&lt;td align='center'&gt;&lt;form action='/' method='get'&gt;"
"&lt;input id='timer' name='timerBtn' value='' class='' type='submit'&gt;&lt;/form&gt;&lt;p&gt;Timer is &lt;span id='timerMsg'&gt;&lt;/span&gt;&lt;/p&gt;"
"&lt;/td&gt;&lt;/tr&gt;"
"&lt;/tbody&gt;"
"&lt;/table&gt;"
"&lt;/div&gt;"
"&lt;/div&gt;"
"&lt;/body&gt;"
"&lt;script&gt;"
"$( document ).ready(function() {"
"setInterval(function(){"
"$('#timerMsg').fadeOut(function () {"
"$(this).fadeIn();"
"});"
"} ,1000);";

// page2 / page2_5 change timer button
// page 3/ page3_5 change current position button
String page2 = "$('#timer').attr({'class': 'btn btn-danger', value: 'TURN OFF'});$('#timerMsg').html('on');});";
String page2_5 = "$('#timer').attr({'class': 'btn btn-success', value: 'TURN ON'});$('#timerMsg').html('off');});";
String page3 = "$('#";
String page3_5 = "').attr({'class': 'btn btn-warning'});";
String page4 = "&lt;/script&gt;&lt;/html&gt;";

void setup(void){

  WiFi.config(ip, gateway, subnet); 
  delay(1000);
  SB(115200);
  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {  
    delay(500);
    SPL("Waiting to connect…");
  }

  SP("IP address: ");
  SPL(WiFi.localIP());

  //here's the same GET request as in Sketch 1 but here it doesn't work
if (WiFi.status() == WL_CONNECTED) {
    HTTPClient http;
    http.begin("http://francescosoave.com/blind/getTime.php?pw=ciao");
    int httpCode = http.GET();
   SP("HTTP: ");
   SPL(httpCode);
    if(httpCode &gt; 0){
      String payload = http.getString();
      SP("PAYLOAD: ");
      SPL(payload);
    }

    http.end();
  }

  server.on("/", control);  
  server.begin();
  SPL("Server listening");
}

int  i = 0;

void loop(void){
  server.handleClient();
}

void control(){

  if(server.args() &gt; 0){ //there is something to change
    if(server.argName(0) == "timerBtn"){
      timerState = !timerState; //change timer
    }else if(server.argName(0) == "manualBtn"){
      curPos = server.arg(0).toInt(); //change current (manual)
    }
  }

  //build the page
  if(timerState)
    pageFinal = page1 + page2;
  else
    pageFinal = page1 + page2_5;

  pageFinal += page3 + curPos + page3_5 + page4;        
  server.send(200, "text/html", pageFinal);
}
</code></pre>

<p>Sketch 2 response in the serial monitor (Tools -> Debug port -> Serial // Tools -> Debug Level -> HTTP_CLIENT)</p>

<pre><code>SDK:2.2.1(cfd48f3)/Core:2.4.1/lwIP:2.0.3(STABLE-2_0_3_RELEASE/glue:arduino-2.4.1)
scandone
Waiting to connectâ€¦
IP address: 192.168.1.7
[HTTP-Client][begin] url: http://francescosoave.com/blind/getTime.php?pw=ciao
[HTTP-Client][begin] host: francescosoave.com port: 80 url: /blind/getTime.php?pw=ciao
[HTTP-Client] failed connect to francescosoave.com:80
[HTTP-Client][returnError] error(-1): connection refused
HTTP: -1
[HTTP-Client][end] tcp is closed
Server listening
pm open,type:2 0
</code></pre>

<p>edit: the issue was in the Wifi.config() line. It should be <code>WiFi.config(ip, gateway, subnet, gateway);</code> </p>
 37622: <p>If you want to configure a static IP address, make sure it is unique in you LAN and outside the range managed by the DHCP server.</p>

<p>EDIT:
the WiFi.config() function doesn't assign the gateway address as DNS address. add 4th parameter with DNS server address.</p>

<pre><code>WiFi.config(ip, gateway, subnet, gateway);
</code></pre>
