Arm Mbed OS support forum

MQTT Problem ( callback function doesn't work)

Hello community,
I have intergated in my program the library [GitHub - ARMmbed/mbed-mqtt: Mbed-os MQTT and MQTT-SN library, based on Eclipse Paho project] in order to achieve MQTT communication with a public test broker, but I encounter a problem with the callback function. Specifically, when a message arrives the callback function that I have defined when subscribing to a topic, it doesn’t be called. Is there any solution?
Thank in responce.