it wont allow me to send messages after the request

#include <DFRobot_SIM808.h>

DFRobot_SIM808 sim808(&Serial);

float lat = 0.0;

float lon = 0.0;

char buffer[512];

char http_cmd[256];

#define PHONE_NUMBER "0884348727"

void setup() {

//mySerial.begin(9600);

Serial.begin(9600);

//******** Initialize sim808 module *************

while (!sim808.init()) {

delay(1000);

Serial.print("Sim808 init error\r\n");

}

//************* Turn on the GPS power************

// sim808_send_cmd()

if (sim808.attachGPS())

Serial.println("Open the GPS power success");

else

Serial.println("Open the GPS power failure");

}

void loop() {

//************** Get GPS data *******************

// Serial.println("attempting to get data ");

if (sim808.getGPS()) {

Serial.print(sim808.GPSdata.year);

Serial.print("/");

Serial.print(sim808.GPSdata.month);

Serial.print("/");

Serial.print(sim808.GPSdata.day);

Serial.print(" ");

Serial.print(sim808.GPSdata.hour);

Serial.print(":");

Serial.print(sim808.GPSdata.minute);

Serial.print(":");

Serial.print(sim808.GPSdata.second);

Serial.print(":");

Serial.println(sim808.GPSdata.centisecond);

Serial.print("latitude :");

Serial.println(sim808.GPSdata.lat,6);

Serial.print("longitude :");

Serial.println(sim808.GPSdata.lon, 6);

Serial.print("speed_kph :");

Serial.println(sim808.GPSdata.speed_kph);

Serial.print("heading :");

Serial.println(sim808.GPSdata.heading);

Serial.println();

lon = sim808.GPSdata.lon, 6;

lat = -sim808.GPSdata.lat, 6;

//************* Turn off the GPS power ************

sim808.detachGPS();

delay(2000);

sendR();

delay(2000);

sendGoogleMapsLink("0884348727");

}

}

void sendR(){

while(!sim808.join(F("internet"))) {

Serial.println("Sim808 join network error");

delay(2000);

}

// char http_cmd ="hello";

// String data = "GET /dumi/send.php?device_id=5555&lat="+ String(lat, 6)+"&lon="+String(lat, 6)+" HTTP/1.1\r\nHost: www.bluecoregames.com\r\n\r\n";

// char http_cmd[] = http_cmd.c_str();

snprintf(http_cmd, sizeof(http_cmd),

"GET /dumi/send.php?device_id=5555&lat=%.6f&lon=%.6f HTTP/1.1\r\nHost: www.bluecoregames.com\r\n\r\n",

lat, lon);

// const char* http_cmd = http_cmd.c_str();

//************ Successful DHCP ****************

Serial.print("IP Address is ");

Serial.println(sim808.getIPAddress());

//*********** Establish a TCP connection ************

if(!sim808.connect(TCP,"www.bluecoregames.com", 80)) {

Serial.println("Connect error");

}else{

Serial.println("Connect bluecore success");

}

//*********** Send a GET request *****************

Serial.println("waiting to fetch...");

sim808.send(http_cmd, sizeof(http_cmd)-1);

while (true) {

int ret = sim808.recv(buffer, sizeof(buffer)-1);

if (ret <= 0){

Serial.println("fetch over...");

break;

}

buffer[ret] = '\0';

Serial.print("Recv: ");

Serial.print(ret);

Serial.print(" bytes: ");

Serial.println(buffer);

break;

}

//************* Close TCP or UDP connections **********

sim808.close();

//*** Disconnect wireless connection, Close Moving Scene *******

sim808.disconnect();

}

void sendGoogleMapsLink(const char *recipient) {

if (lat != 0.0 && lon != 0.0) {

String googleMapsLink = "https://www.google.com/maps?q=" + String(lat, 6) + "," + String(lon, 6);

if (sim808.sendSMS(recipient, googleMapsLink.c_str())) {

Serial.println("Sent SMS with Google Maps link: " + googleMapsLink);

} else {

Serial.println("Failed to send SMS.");

}

} else {

Serial.println("GPS data unavailable, cannot send link.");

}

}