Certificate issue with ESP32 using MQTTClient

Question

Hello,

I have an issue connecting to my IoT Endpoint in IoT Core.
I'm using the example from https://github.com/aws-samples/aws-iot-esp32-arduino-examples/tree/master/examples/basic-pubsub
I've registered my ESP32 as a thing, created a policy (with wildcards *), and attached the certificates to the policy. I also tried attaching the certificates to the thing. I changed the code in the example to match the name of my thing, and I provided the certificates and the private key in `secrets.h`
Now my ESP32 cannot connect, and I get the error  `-3`, which translates to `"LWMQTT_NETWORK_FAILED_CONNECT"`

As Root CA, I'm using AmazonRootCA1, I also re-created the certificates.
When I took a trace , I saw that during the TLS negotiating phase, my ESP32 answers with an `"Unknown CA"` alter and closed the connection.
![Enter image description here](/media/postImages/original/IMRp3z7UYHQc2EsFC1hL1rMg)

This is keeping me busy already for a few days. Any idea on how I can debug (or fix) this?

Kr,
Wim

Accepted Answer

Hi. Are you trying to connect to the ATS endpoint (you should be)?

https://docs.aws.amazon.com/iot/latest/developerguide/server-authentication.html#endpoint-types

Answer

Hello Greg,

Thanks for pointing me in the right direction.
Indeed, I was pointing to a fault endpoint: `.iot.your-region.amazonaws.com`, 
while it should have been:  `-ats.iot.your-region.amazonaws.com`

I found it out when I issued the command `aws iot describe-endpoint --endpoint-type iot:Data-ATS`

Thanks for the swift reply!
--
Wim

Certificate issue with ESP32 using MQTTClient

Thanks for the swift reply!

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