I am trying to make X-CUBE-GCP working but till now there is no any sign of success. The major issues I am facing is with mqtt connection not being established.

[PDutt.2]

As shown above, the error is coming after jwt is created successfully. I checked the default mqtt hostname is not working with my sample python code.

I changed the hostname to mqtt.googleapis.com and port number but still facing same issue.As suggested in documentation, I thought the problem is with firmware and tried to updated the firmware with gcp storage account. But there is no success updating the firmware- 

Please suggest whether there are any missing steps. I need to make this quickstart demo working before I can start the actual development. Thanks

[Duy Tran]

If you readback the log, you will see that the JWT was not created properly - error 711. There are several reasons for this, but mostly are from user side. For me I was entering the wrong private key.

[PDutt.2]

Duy, Thanks for the reply. I am really stuck working with this SDK. I properly checked public private key pair and resolved all issues mentioned in this post. I was able to make it working and sensor values were getting published on the portal properly.

However, I needed to erase the board and tried to again follow the same process. Now I am facing root CA certificate authentication error. I am sure that I am using the same certificate as mentioned in the SDK path "Middlewares\Third_Party\GCP\samples\STM32Cube\globalsign_usertrust.pem" which was working last time. But now I am getting following error as shown in image.

I looked into full root CA list (https://pki.goog/roots.pem) and tried to pass full CA list but it is not understandable which key to actually use.

I have already invested more than 2 days trying to fix it. Please help!

[PDutt.2]

Posted the answer in a separate thread: https://community.st.com/s/question/0D53W00000V21WUSAZ/urgent-xcubegcp-the-certificate-is-not-correctly-signed-by-the-trusted-ca-issue