POST request using WiFiEsp.h library

Question

I'm using an arduino uno and ESP8266 (esp01) with the WiFiEsp library to connect to WiFi and POST data, connecting to WiFi works just fine.

I need to send a POST request, but I can't get it to work as I want.

 #include "WiFiEsp.h"
 // Emulate Serial1 on pins 7/8 if not present
 #ifndef HAVE_HWSERIAL1
 #include "SoftwareSerial.h"
 SoftwareSerial Serial1(6, 7); // RX, TX
 #endif
 char ssid[] = "Innovating-Guest"; // your network SSID (name)
 char pass[] = "wireless"; // your network password
 int status = WL_IDLE_STATUS; // the Wifi radio's status

 char server[] = "10.66.240.66";//http://10.66.240.66:8000/loadimage
 WiFiEspClient client; // Initialize the Ethernet client object

 void setup()
 {
 // initialize serial for debugging
 Serial.begin(9600);
 // initialize serial for ESP module
 Serial1.begin(9600);
 // initialize ESP module
 WiFi.init(&Serial1);
 // check for the presence of the shield
 if (WiFi.status() == WL_NO_SHIELD) 
 {
 Serial.println("WiFi shield not present");
 // don't continue
 while (true);
 }

 // attempt to connect to WiFi network
 while ( status != WL_CONNECTED) {
 Serial.print("Attempting to connect to WPA SSID: ");
 Serial.println(ssid);
 // Connect to WPA/WPA2 network
 status = WiFi.begin(ssid, pass);
 }
 // you're connected now, so print out the data
 Serial.println("You're connected to the network");
 printWifiStatus();
 Serial.println();
 Serial.println("Starting connection to server...");
 // if you get a connection, report back via serial
 if (client.connect(server, 8000)) {
 Serial.println("Connected to server");
 String temp= "12.22";
 String humd= "23.33";
 String batt= "100";

 String content ="{\"temperature\": + temp +,\"humidity\":+ humd +,\"batteryPer\": + batt + }";
 client.println("POST /loadimage HTTP/1.1");
 client.println("Host: 10.66.240.66:8000");
 client.println("Accept: */*");
 client.print("Content-Length: ");
 client.println(content.length());
 client.println("Content-Type: application/json");
 client.println();
 client.println(content);
 }
 }
 void loop()
 {

 while (client.available()) {
 char c = client.read();
 Serial.write(c);
 }
 // if the server's disconnected, stop the client
 if (!client.connected()) {
 Serial.println();
 Serial.println("Disconnecting from server...");
 client.stop();
 // do nothing forevermore
 while (true);
  }
 }

 void printWifiStatus()
 {
 // print the SSID of the network you're attached to
 Serial.print("SSID: ");
 Serial.println(WiFi.SSID());

 // print your WiFi shield's IP address
 IPAddress ip = WiFi.localIP();
 Serial.print("IP Address: ");
 Serial.println(ip);

 // print the received signal strength
 long rssi = WiFi.RSSI();
 Serial.print("Signal strength (RSSI):");
 Serial.print(rssi);
 Serial.println(" dBm");
 }

Can anyone help me to know that why this error is coming.

Thanks in advance.