user89179:     Arduino: 1.8.14 Hourly Build 2020/12/15 11:33 (Windows 10), Board: "Generic ESP8266 Module, 80 MHz, Flash, Disabled (new aborts on oom), Disabled, All SSL ciphers (most compatible), 32KB cache + 32KB IRAM (balanced), Use pgm_read macros for IRAM/PROGMEM, dtr (aka nodemcu), 26 MHz, 40MHz, DOUT (compatible), 1MB (FS:64KB OTA:~470KB), 2, nonos-sdk 2.2.1+100 (190703), v2 Lower Memory, Disabled, None, Only Sketch, 115200"

In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:4:
    
    C:\Users\JUNAID\Documents\Arduino\libraries\ESPAsyncWebServer-master\src/ESPAsyncWebServer.h:62:18: error: 'HTTP_GET' conflicts with a previous declaration
    
       62 |   HTTP_GET     = 0b00000001,
    
          |                  ^~~~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:2:
    
    C:\Users\JUNAID\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\3.0.0\libraries\ESP8266WebServer\src/ESP8266WebServer.h:47:29: note: previous declaration 'HTTPMethod HTTP_GET'
    
       47 | enum HTTPMethod { HTTP_ANY, HTTP_GET, HTTP_HEAD, HTTP_POST, HTTP_PUT, HTTP_PATCH, HTTP_DELETE, HTTP_OPTIONS };
    
          |                             ^~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:4:
    
    C:\Users\JUNAID\Documents\Arduino\libraries\ESPAsyncWebServer-master\src/ESPAsyncWebServer.h:63:18: error: 'HTTP_POST' conflicts with a previous declaration
    
       63 |   HTTP_POST    = 0b00000010,
    
          |                  ^~~~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:2:
    
    C:\Users\JUNAID\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\3.0.0\libraries\ESP8266WebServer\src/ESP8266WebServer.h:47:50: note: previous declaration 'HTTPMethod HTTP_POST'
    
       47 | enum HTTPMethod { HTTP_ANY, HTTP_GET, HTTP_HEAD, HTTP_POST, HTTP_PUT, HTTP_PATCH, HTTP_DELETE, HTTP_OPTIONS };
    
          |                                                  ^~~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:4:
    
    C:\Users\JUNAID\Documents\Arduino\libraries\ESPAsyncWebServer-master\src/ESPAsyncWebServer.h:64:18: error: 'HTTP_DELETE' conflicts with a previous declaration
    
       64 |   HTTP_DELETE  = 0b00000100,
    
          |                  ^~~~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:2:
    
    C:\Users\JUNAID\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\3.0.0\libraries\ESP8266WebServer\src/ESP8266WebServer.h:47:83: note: previous declaration 'HTTPMethod HTTP_DELETE'
    
       47 | enum HTTPMethod { HTTP_ANY, HTTP_GET, HTTP_HEAD, HTTP_POST, HTTP_PUT, HTTP_PATCH, HTTP_DELETE, HTTP_OPTIONS };
    
          |                                                                                   ^~~~~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:4:
    
    C:\Users\JUNAID\Documents\Arduino\libraries\ESPAsyncWebServer-master\src/ESPAsyncWebServer.h:65:18: error: 'HTTP_PUT' conflicts with a previous declaration
    
       65 |   HTTP_PUT     = 0b00001000,
    
          |                  ^~~~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:2:
    
    C:\Users\JUNAID\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\3.0.0\libraries\ESP8266WebServer\src/ESP8266WebServer.h:47:61: note: previous declaration 'HTTPMethod HTTP_PUT'
    
       47 | enum HTTPMethod { HTTP_ANY, HTTP_GET, HTTP_HEAD, HTTP_POST, HTTP_PUT, HTTP_PATCH, HTTP_DELETE, HTTP_OPTIONS };
    
          |                                                             ^~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:4:
    
    C:\Users\JUNAID\Documents\Arduino\libraries\ESPAsyncWebServer-master\src/ESPAsyncWebServer.h:66:18: error: 'HTTP_PATCH' conflicts with a previous declaration
    
       66 |   HTTP_PATCH   = 0b00010000,
    
          |                  ^~~~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:2:
    
    C:\Users\JUNAID\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\3.0.0\libraries\ESP8266WebServer\src/ESP8266WebServer.h:47:71: note: previous declaration 'HTTPMethod HTTP_PATCH'
    
       47 | enum HTTPMethod { HTTP_ANY, HTTP_GET, HTTP_HEAD, HTTP_POST, HTTP_PUT, HTTP_PATCH, HTTP_DELETE, HTTP_OPTIONS };
    
          |                                                                       ^~~~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:4:
    
    C:\Users\JUNAID\Documents\Arduino\libraries\ESPAsyncWebServer-master\src/ESPAsyncWebServer.h:67:18: error: 'HTTP_HEAD' conflicts with a previous declaration
    
       67 |   HTTP_HEAD    = 0b00100000,
    
          |                  ^~~~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:2:
    
    C:\Users\JUNAID\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\3.0.0\libraries\ESP8266WebServer\src/ESP8266WebServer.h:47:39: note: previous declaration 'HTTPMethod HTTP_HEAD'
    
       47 | enum HTTPMethod { HTTP_ANY, HTTP_GET, HTTP_HEAD, HTTP_POST, HTTP_PUT, HTTP_PATCH, HTTP_DELETE, HTTP_OPTIONS };
    
          |                                       ^~~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:4:
    
    C:\Users\JUNAID\Documents\Arduino\libraries\ESPAsyncWebServer-master\src/ESPAsyncWebServer.h:68:18: error: 'HTTP_OPTIONS' conflicts with a previous declaration
    
       68 |   HTTP_OPTIONS = 0b01000000,
    
          |                  ^~~~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:2:
    
    C:\Users\JUNAID\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\3.0.0\libraries\ESP8266WebServer\src/ESP8266WebServer.h:47:96: note: previous declaration 'HTTPMethod HTTP_OPTIONS'
    
       47 | enum HTTPMethod { HTTP_ANY, HTTP_GET, HTTP_HEAD, HTTP_POST, HTTP_PUT, HTTP_PATCH, HTTP_DELETE, HTTP_OPTIONS };
    
          |                                                                                                ^~~~~~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:4:
    
    C:\Users\JUNAID\Documents\Arduino\libraries\ESPAsyncWebServer-master\src/ESPAsyncWebServer.h:69:18: error: 'HTTP_ANY' conflicts with a previous declaration
    
       69 |   HTTP_ANY     = 0b01111111,
    
          |                  ^~~~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:2:
    
    C:\Users\JUNAID\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\3.0.0\libraries\ESP8266WebServer\src/ESP8266WebServer.h:47:19: note: previous declaration 'HTTPMethod HTTP_ANY'
    
       47 | enum HTTPMethod { HTTP_ANY, HTTP_GET, HTTP_HEAD, HTTP_POST, HTTP_PUT, HTTP_PATCH, HTTP_DELETE, HTTP_OPTIONS };
    
          |                   ^~~~~~~~
    
    Multiple libraries were found for "ESPAsyncTCP.h"
    
     Used: C:\Users\JUNAID\Documents\Arduino\libraries\ESPAsyncTCP
    
     Not used: C:\Users\JUNAID\Documents\Arduino\libraries\ESPAsyncTCP-master
    
    exit status 1
    
    Error compiling for board Generic ESP8266 Module.
    
    
    
    This report would have more information with
    "Show verbose output during compilation"
    option enabled in File -> Preferences.

code
#include <ESP8266WiFi.h>
#include <ESP8266WebServer.h>
#include <ESPAsyncTCP.h>
#include <ESPAsyncWebServer.h>
int Wifiled = 15;
  
ESP8266WebServer esp(80);

String HTML = "";
       
String FORM = "testing the second website";




void setup() 
{         
       HTML +="<html>";
       HTML +=  "<head>";
       HTML +=    "<title>MY SMART HOME</title>"; 
       HTML +="<style>";
       HTML +="body {background-color:#92e8e2;}";
       HTML +="#wrapper {background-color:#ebf5f4;width:93%;min-height:700px;margin:auto;barder:1px solid #ccc;padding:10px;}";
       HTML +="</style>";       
       
       HTML +=  "</head>";
       HTML +=  "<body>";
       HTML +=  "<div id='wrapper'>";    
       HTML +=    "<h3>WELCOME TO MY SMART SENSOR DATA</h3>";
       HTML +=    "<h2>PH SENSOR DATA   </h2>";
       HTML +=    "Serial.monitor";
       HTML +=    "<h2>EC SENSOR DATA </h2>";
       HTML +=  "</div >"; 
       HTML +=  "</body>";    
       HTML +="</html>";   
    pinMode(Wifiled,OUTPUT);
    delay(1000);
    Serial.begin(115200);
    WiFi.begin("LAPTOP","123456789");
    while(WiFi.status() != WL_CONNECTED)
    {
          Serial.print(".");
          digitalWrite(Wifiled,HIGH);
          delay(250);
          digitalWrite(Wifiled,LOW);
          delay(250);          
    }
        digitalWrite(Wifiled,HIGH);
        Serial.println("wifi connected");
        Serial.println(WiFi.localIP());



        esp.on("/",sendHtml);
        esp.on("/process",sendform);
        esp.begin();
}
void sendform()
{
  esp.send(200,"text/html;",FORM);
}

void sendHtml()
{
  esp.send(200,"text/html;",HTML);
  
}

void loop() 
{
   esp.handleClient();
   delay(200);
   char buffer[20]="";
   if(Serial.available()>0){
  //  char data=Serial.read();
   Serial.readBytesUntil('\n',buffer,20);
   Serial.println(buffer);
   }
}


user521: You've included <ESP8266WebServer.h> and <ESPAsyncWebServer.h>, it's one or the other, you can't have both. Hence you're getting error: 'HTTP_GET' conflicts with a previous declaration

89179: <pre><code>    Arduino: 1.8.14 Hourly Build 2020/12/15 11:33 (Windows 10), Board: &quot;Generic ESP8266 Module, 80 MHz, Flash, Disabled (new aborts on oom), Disabled, All SSL ciphers (most compatible), 32KB cache + 32KB IRAM (balanced), Use pgm_read macros for IRAM/PROGMEM, dtr (aka nodemcu), 26 MHz, 40MHz, DOUT (compatible), 1MB (FS:64KB OTA:~470KB), 2, nonos-sdk 2.2.1+100 (190703), v2 Lower Memory, Disabled, None, Only Sketch, 115200&quot;

In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:4:
    
    C:\Users\JUNAID\Documents\Arduino\libraries\ESPAsyncWebServer-master\src/ESPAsyncWebServer.h:62:18: error: 'HTTP_GET' conflicts with a previous declaration
    
       62 |   HTTP_GET     = 0b00000001,
    
          |                  ^~~~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:2:
    
    C:\Users\JUNAID\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\3.0.0\libraries\ESP8266WebServer\src/ESP8266WebServer.h:47:29: note: previous declaration 'HTTPMethod HTTP_GET'
    
       47 | enum HTTPMethod { HTTP_ANY, HTTP_GET, HTTP_HEAD, HTTP_POST, HTTP_PUT, HTTP_PATCH, HTTP_DELETE, HTTP_OPTIONS };
    
          |                             ^~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:4:
    
    C:\Users\JUNAID\Documents\Arduino\libraries\ESPAsyncWebServer-master\src/ESPAsyncWebServer.h:63:18: error: 'HTTP_POST' conflicts with a previous declaration
    
       63 |   HTTP_POST    = 0b00000010,
    
          |                  ^~~~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:2:
    
    C:\Users\JUNAID\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\3.0.0\libraries\ESP8266WebServer\src/ESP8266WebServer.h:47:50: note: previous declaration 'HTTPMethod HTTP_POST'
    
       47 | enum HTTPMethod { HTTP_ANY, HTTP_GET, HTTP_HEAD, HTTP_POST, HTTP_PUT, HTTP_PATCH, HTTP_DELETE, HTTP_OPTIONS };
    
          |                                                  ^~~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:4:
    
    C:\Users\JUNAID\Documents\Arduino\libraries\ESPAsyncWebServer-master\src/ESPAsyncWebServer.h:64:18: error: 'HTTP_DELETE' conflicts with a previous declaration
    
       64 |   HTTP_DELETE  = 0b00000100,
    
          |                  ^~~~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:2:
    
    C:\Users\JUNAID\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\3.0.0\libraries\ESP8266WebServer\src/ESP8266WebServer.h:47:83: note: previous declaration 'HTTPMethod HTTP_DELETE'
    
       47 | enum HTTPMethod { HTTP_ANY, HTTP_GET, HTTP_HEAD, HTTP_POST, HTTP_PUT, HTTP_PATCH, HTTP_DELETE, HTTP_OPTIONS };
    
          |                                                                                   ^~~~~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:4:
    
    C:\Users\JUNAID\Documents\Arduino\libraries\ESPAsyncWebServer-master\src/ESPAsyncWebServer.h:65:18: error: 'HTTP_PUT' conflicts with a previous declaration
    
       65 |   HTTP_PUT     = 0b00001000,
    
          |                  ^~~~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:2:
    
    C:\Users\JUNAID\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\3.0.0\libraries\ESP8266WebServer\src/ESP8266WebServer.h:47:61: note: previous declaration 'HTTPMethod HTTP_PUT'
    
       47 | enum HTTPMethod { HTTP_ANY, HTTP_GET, HTTP_HEAD, HTTP_POST, HTTP_PUT, HTTP_PATCH, HTTP_DELETE, HTTP_OPTIONS };
    
          |                                                             ^~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:4:
    
    C:\Users\JUNAID\Documents\Arduino\libraries\ESPAsyncWebServer-master\src/ESPAsyncWebServer.h:66:18: error: 'HTTP_PATCH' conflicts with a previous declaration
    
       66 |   HTTP_PATCH   = 0b00010000,
    
          |                  ^~~~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:2:
    
    C:\Users\JUNAID\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\3.0.0\libraries\ESP8266WebServer\src/ESP8266WebServer.h:47:71: note: previous declaration 'HTTPMethod HTTP_PATCH'
    
       47 | enum HTTPMethod { HTTP_ANY, HTTP_GET, HTTP_HEAD, HTTP_POST, HTTP_PUT, HTTP_PATCH, HTTP_DELETE, HTTP_OPTIONS };
    
          |                                                                       ^~~~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:4:
    
    C:\Users\JUNAID\Documents\Arduino\libraries\ESPAsyncWebServer-master\src/ESPAsyncWebServer.h:67:18: error: 'HTTP_HEAD' conflicts with a previous declaration
    
       67 |   HTTP_HEAD    = 0b00100000,
    
          |                  ^~~~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:2:
    
    C:\Users\JUNAID\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\3.0.0\libraries\ESP8266WebServer\src/ESP8266WebServer.h:47:39: note: previous declaration 'HTTPMethod HTTP_HEAD'
    
       47 | enum HTTPMethod { HTTP_ANY, HTTP_GET, HTTP_HEAD, HTTP_POST, HTTP_PUT, HTTP_PATCH, HTTP_DELETE, HTTP_OPTIONS };
    
          |                                       ^~~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:4:
    
    C:\Users\JUNAID\Documents\Arduino\libraries\ESPAsyncWebServer-master\src/ESPAsyncWebServer.h:68:18: error: 'HTTP_OPTIONS' conflicts with a previous declaration
    
       68 |   HTTP_OPTIONS = 0b01000000,
    
          |                  ^~~~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:2:
    
    C:\Users\JUNAID\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\3.0.0\libraries\ESP8266WebServer\src/ESP8266WebServer.h:47:96: note: previous declaration 'HTTPMethod HTTP_OPTIONS'
    
       47 | enum HTTPMethod { HTTP_ANY, HTTP_GET, HTTP_HEAD, HTTP_POST, HTTP_PUT, HTTP_PATCH, HTTP_DELETE, HTTP_OPTIONS };
    
          |                                                                                                ^~~~~~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:4:
    
    C:\Users\JUNAID\Documents\Arduino\libraries\ESPAsyncWebServer-master\src/ESPAsyncWebServer.h:69:18: error: 'HTTP_ANY' conflicts with a previous declaration
    
       69 |   HTTP_ANY     = 0b01111111,
    
          |                  ^~~~~~~~~~
    
    In file included from C:\Users\JUNAID\Documents\Arduino\iot_project_4\iot_project_4.ino:2:
    
    C:\Users\JUNAID\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\3.0.0\libraries\ESP8266WebServer\src/ESP8266WebServer.h:47:19: note: previous declaration 'HTTPMethod HTTP_ANY'
    
       47 | enum HTTPMethod { HTTP_ANY, HTTP_GET, HTTP_HEAD, HTTP_POST, HTTP_PUT, HTTP_PATCH, HTTP_DELETE, HTTP_OPTIONS };
    
          |                   ^~~~~~~~
    
    Multiple libraries were found for &quot;ESPAsyncTCP.h&quot;
    
     Used: C:\Users\JUNAID\Documents\Arduino\libraries\ESPAsyncTCP
    
     Not used: C:\Users\JUNAID\Documents\Arduino\libraries\ESPAsyncTCP-master
    
    exit status 1
    
    Error compiling for board Generic ESP8266 Module.
    
    
    
    This report would have more information with
    &quot;Show verbose output during compilation&quot;
    option enabled in File -&gt; Preferences.
</code></pre>
<p>code</p>
<pre><code>#include &lt;ESP8266WiFi.h&gt;
#include &lt;ESP8266WebServer.h&gt;
#include &lt;ESPAsyncTCP.h&gt;
#include &lt;ESPAsyncWebServer.h&gt;
int Wifiled = 15;
  
ESP8266WebServer esp(80);

String HTML = &quot;&quot;;
       
String FORM = &quot;testing the second website&quot;;




void setup() 
{         
       HTML +=&quot;&lt;html&gt;&quot;;
       HTML +=  &quot;&lt;head&gt;&quot;;
       HTML +=    &quot;&lt;title&gt;MY SMART HOME&lt;/title&gt;&quot;; 
       HTML +=&quot;&lt;style&gt;&quot;;
       HTML +=&quot;body {background-color:#92e8e2;}&quot;;
       HTML +=&quot;#wrapper {background-color:#ebf5f4;width:93%;min-height:700px;margin:auto;barder:1px solid #ccc;padding:10px;}&quot;;
       HTML +=&quot;&lt;/style&gt;&quot;;       
       
       HTML +=  &quot;&lt;/head&gt;&quot;;
       HTML +=  &quot;&lt;body&gt;&quot;;
       HTML +=  &quot;&lt;div id='wrapper'&gt;&quot;;    
       HTML +=    &quot;&lt;h3&gt;WELCOME TO MY SMART SENSOR DATA&lt;/h3&gt;&quot;;
       HTML +=    &quot;&lt;h2&gt;PH SENSOR DATA   &lt;/h2&gt;&quot;;
       HTML +=    &quot;Serial.monitor&quot;;
       HTML +=    &quot;&lt;h2&gt;EC SENSOR DATA &lt;/h2&gt;&quot;;
       HTML +=  &quot;&lt;/div &gt;&quot;; 
       HTML +=  &quot;&lt;/body&gt;&quot;;    
       HTML +=&quot;&lt;/html&gt;&quot;;   
    pinMode(Wifiled,OUTPUT);
    delay(1000);
    Serial.begin(115200);
    WiFi.begin(&quot;LAPTOP&quot;,&quot;123456789&quot;);
    while(WiFi.status() != WL_CONNECTED)
    {
          Serial.print(&quot;.&quot;);
          digitalWrite(Wifiled,HIGH);
          delay(250);
          digitalWrite(Wifiled,LOW);
          delay(250);          
    }
        digitalWrite(Wifiled,HIGH);
        Serial.println(&quot;wifi connected&quot;);
        Serial.println(WiFi.localIP());



        esp.on(&quot;/&quot;,sendHtml);
        esp.on(&quot;/process&quot;,sendform);
        esp.begin();
}
void sendform()
{
  esp.send(200,&quot;text/html;&quot;,FORM);
}

void sendHtml()
{
  esp.send(200,&quot;text/html;&quot;,HTML);
  
}

void loop() 
{
   esp.handleClient();
   delay(200);
   char buffer[20]=&quot;&quot;;
   if(Serial.available()&gt;0){
  //  char data=Serial.read();
   Serial.readBytesUntil('\n',buffer,20);
   Serial.println(buffer);
   }
}
</code></pre>
 521: <p>You've included &lt;ESP8266WebServer.h&gt; and &lt;ESPAsyncWebServer.h&gt;, it's one or the other, you can't have both. Hence you're getting error: 'HTTP_GET' conflicts with a previous declaration</p>
