error: Invalid MQTT message type: 11 when trying to publish message

[Prem326]

I am using apollo broker and libmosquitto C library to connect with the broker. Whenever I try to publish any message to the broker, the following error message is recorded in logs in my brokers home directory.
Following is the code snippet that i have been using

void on_publish(struct mosquitto *mosq, void *userdata, int mid)
{
log_print("mqtt",1,"Inside publish callback");
}

int sendData_mqtt(char *address, char *port,char *url,char *data) {
int err;
char *clean_session = "true";
char *retain_flag = "true";
int port1 = atoi(port);
struct mosquitto *mosq;

mosq = mosquitto_new("Mqtt", clean_session, NULL);
mosquitto_publish_callback_set(mosq, on_publish);

mosquitto_username_pw_set(mosq,"admin","password"); 
err=mosquitto_connect(mosq, address, port1,60);

if(err != 0 ){
    log_print("mqtt",1,"connect error= %s\n",mosquitto_strerror(err));
    return -1;
}

mosquitto_publish(mosq, NULL, "Mqtt", strlen(data), data, 1, retain_flag);

mosquitto_loop_forever(mosq, -1, 1);
return 0;   

}

The weird thing is when i use the above program independently, it works fine but currently some other function in some other file is calling senddata_mqtt and in that case it throws the error which I stated above. Please help me know what is going on here.