Now I update MQTT-TLS library to 0.2.27.
Some guys have trouble with mbedtls config for Azure/AWS connection, so I update the library defualt config settings set up to be lightweight with a default setting that can connect to Azure/AWS/test mosquitto org (let's encrypt).
I tested with AWS IoT, Azure IoT core, test mosquitto org works well.
exp) How to connect Azure IoT Hub with MQTT-TLS
Thank you.