Esp8266 and an RFID RC522

I have made a card reader with an esp8266 and an RFID RC522 from this home page

https://www.aranacorp.com/en/using-an-rfid-module-with-an-esp8266/

and taken the code from the site, but it doesn't work??

#include <SPI.h>
#include <MFRC522.h>
#define SS_PIN D8
#define RST_PIN D0
MFRC522 rfid(SS_PIN, RST_PIN); // Instance of the class
MFRC522::MIFARE_Key key;
// Init array that will store new NUID
byte nuidPICC[4];
void setup() {
 	Serial.begin(115200);
 	SPI.begin(); // Init SPI bus
 	rfid.PCD_Init(); // Init MFRC522
 	Serial.println();
 	Serial.print(F("Reader :"));
 	rfid.PCD_DumpVersionToSerial();
 	for (byte i = 0; i < 6; i++) {
 			key.keyByte[i] = 0xFF;
 	}
 	Serial.println();
 	Serial.println(F("This code scan the MIFARE Classic NUID."));
 	Serial.print(F("Using the following key:"));
 	printHex(key.keyByte, MFRC522::MF_KEY_SIZE);
}
void loop() {
 	// Reset the loop if no new card present on the sensor/reader. This saves the entire process when idle.
 	if ( ! rfid.PICC_IsNewCardPresent())
 			return;
 	// Verify if the NUID has been readed
 	if ( ! rfid.PICC_ReadCardSerial())
 			return;
 	Serial.print(F("PICC type: "));
 	MFRC522::PICC_Type piccType = rfid.PICC_GetType(rfid.uid.sak);
 	Serial.println(rfid.PICC_GetTypeName(piccType));
 	// Check is the PICC of Classic MIFARE type
 	if (piccType != MFRC522::PICC_TYPE_MIFARE_MINI &&
 					piccType != MFRC522::PICC_TYPE_MIFARE_1K &&
 					piccType != MFRC522::PICC_TYPE_MIFARE_4K) {
 			Serial.println(F("Your tag is not of type MIFARE Classic."));
 			return;
 	}
 	if (rfid.uid.uidByte[0] != nuidPICC[0] ||
 					rfid.uid.uidByte[1] != nuidPICC[1] ||
 					rfid.uid.uidByte[2] != nuidPICC[2] ||
 					rfid.uid.uidByte[3] != nuidPICC[3] ) {
 			Serial.println(F("A new card has been detected."));
 			// Store NUID into nuidPICC array
 			for (byte i = 0; i < 4; i++) {
 					nuidPICC[i] = rfid.uid.uidByte[i];
 			}
 			Serial.println(F("The NUID tag is:"));
 			Serial.print(F("In hex: "));
 			printHex(rfid.uid.uidByte, rfid.uid.size);
 			Serial.println();
 			Serial.print(F("In dec: "));
 			printDec(rfid.uid.uidByte, rfid.uid.size);
 			Serial.println();
 	}
 	else Serial.println(F("Card read previously."));
 	// Halt PICC
 	rfid.PICC_HaltA();
 	// Stop encryption on PCD
 	rfid.PCD_StopCrypto1();
}
/**
 		Helper routine to dump a byte array as hex values to Serial.
*/
void printHex(byte *buffer, byte bufferSize) {
 	for (byte i = 0; i < bufferSize; i++) {
 			Serial.print(buffer[i] < 0x10 ? " 0" : " ");
 			Serial.print(buffer[i], HEX);
 	}
}
/**
 		Helper routine to dump a byte array as dec values to Serial.
*/
void printDec(byte *buffer, byte bufferSize) {
 	for (byte i = 0; i < bufferSize; i++) {
 			Serial.print(buffer[i] < 0x10 ? " 0" : " ");
 			Serial.print(buffer[i], DEC);
 	}
}