Newbie trying to get MQTT work with Arduino

First time using Home Assistant 2021.2.3.

My arduino code:
client.publish("Arduinotesti", temp1Char);

Supervisor > Mosquito broker > log says:
1613411571: New client connected from 192.168.1.143 as ardu (p2, c1, k15).

Should Configuration > MQTT broker > configure > type Arduinotesti > start listening show the values from Arduino? It doesnt… Arduino is sending temperature values every 5 seconds. How could I get those numbers to HA?

Also on other machine I have MQTT.fx which connects to HA ip MQTT server but also doesnt show anything if Arduinotesti subscribed.

Did you use the correct username and password for the client to connect? If you havent changed the default config of the mosquito addon in HA, then the mqtt username and password will be same as that of HA user.

Please show your complete Arduino code.

If you are not seeing anything published in MQTT.fx (try MQTT Explorer…much better) then likely there is a code issue.