MQTT subscribing is not working

Hello Experts,

I am not able to subscribe (receive) the data in arduino board.
I am using ethernet shield and arduino UNO.

Any help ?

#include <Ethernet.h>
#include <PubSubClient.h>
 
// Update these with values suitable for your network.
byte mac[]    = {  0xDE, 0xED, 0xBA, 0xFE, 0xFE, 0xED };
IPAddress ip(192, 168, 0, 110);
IPAddress server(192, 168, 0, 123);
 
void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("Message arrived [");
  Serial.print(topic);
  Serial.print("] ");
  for (int i=0;i<length;i++) {
    Serial.print((char)payload[i]);
  }
  Serial.println();
}
 
EthernetClient ethClient;
PubSubClient mqttClient(ethClient);
 
void reconnect() {
  // Loop until we're reconnected
  while (!mqttClient.connected()) {
    Serial.print("Attempting MQTT connection...");
    // Attempt to connect
    if (mqttClient.connect("arduinoClient")) {
      Serial.println("connected");
      // Once connected, publish an announcement...
      mqttClient.publish("outTopic","hello world");
      // ... and resubscribe
      mqttClient.subscribe("inTopic");
    } else {
      Serial.print("failed, rc=");
      Serial.print(mqttClient.state());
      Serial.println(" try again in 5 seconds");
      // Wait 5 seconds before retrying
      delay(5000);
    }
  }
}
 
void setup()
{
  Serial.begin(9600);
 
  mqttClient.setServer(server, 1883);
  mqttClient.setCallback(callback);
 
  Ethernet.begin(mac, ip);
  // Allow the hardware to sort itself out
  delay(1500);
}
 
void loop()
{
  if (!mqttClient.connected()) {
    reconnect();
  }
  mqttClient.loop();
}

Regards,
Titus S.