Arduino Uno Wifi send data to Thingspeak using MQTT | Arduino | Forum

Hello, I'm discovering the world of arduino in my IT degree and I have a project where I want to send data to Thingspeak first and then try to set up a MQTT server on a raspberry pi.
So I've done some research and code that programe, but nothing seems to appear on my Thingspeak channel. I'm using an Arduino Uno Wifi and I've configure the connectivity panel in the web interface like this :

Server hostname : mqtt.thingspeak.com
Server port : 1883
Client ID : arduino
Client timeout : 2
Keep Alive Interval : 60
and nothing in the remaining fields

And my code is the following :

#include
#include

#define CONNECTOR "mqtt"
#define quai1_topic "channels/743601/publish/fields/field1/P16A40KF8872H8DA"
#define quai2_topic "channels/743601/publish/fields/field2/P16A40KF8872H8DA"

void setup() {
Serial.begin(115200);
Ciao.begin();
}

void loop(){
static int counter = 0;

Ciao.write(CONNECTOR, quai1_topic, String(micros()));
Ciao.write(CONNECTOR, quai2_topic, String(counter));

++counter;
delay(20000);
}

But I'm receiving nothing on my thingspeak channels, so if someone have a clue to help me I would be thankfull to him.
Thanks again and have a nice day