STM32L4 discovary board AWS IoT Tera Term Error

This is the error, I forgot to attach the image:

Hi Obinex. I dusted off my STM32L4 and went through the quick start. Everything worked fine.

You should be receiving either nothing, or a 2-byte CONNACK. Instead you're getting some kind of truncated or seemingly corrupt response that is not any kind of valid MQTT message. Assuming you didn't modify the firmware, I don't have a theory on what's wrong here. And we already checked the policy on your other question. I suggest you open a GitHub issue here: https://github.com/aws/amazon-freertos/issues