AWS IDT MQTT case, got unexpected alert message, mbedtls returned -0x7880

[jun.luo]

@aggarg

That strongly indicates some issue with your certificate (or attached policy). How did you create your device certificate? Lets first test that certificate in isolation to narrow down the problem. You can use mosquitto client for that:

My understanding is that because i’m running the cases under IOT Device Tester, so the device certificate and private key is auto-created by the IDT and updated in aws_clientcredential_keys.h(keyCLIENT_CERTIFICATE_PEM/keyCLIENT_PRIVATE_KEY_PEM)
And meanwhile when running the cases, i check the policy attached with the thing in the AWS IOT web page, the policy allow “" for action "iot:”, so i can’t find any problem with the certificate and policy. You can correct me if my understanding is wrong.