Weird output from serial port

[Ivan Popov]

Hello,

In short, my use case is that I'm trying to onboard a Thingy:91 to AWS IoT Core through the available code sample following this tutorial (and the related library description linked in it).

What I did successfully was: 

1. I managed to provision the certificates to the device (I can see them listed along with the default ones with the AT%CMNG=1 command).
2. I created a project from the sample (aws_iot), edited the required properties (AWS MQTT endpoint, device_id, topics, ...) and managed to build it in VSCode for the thingy91_nrf9160_ns target.
3. I flashed the resulting app_signed.hex file on the device with the Programmer application (it took ~50 seconds).

However, on rebooting the device in regular mode I get nothing in AWS IoT Core - nothing in the topics, nothing for the shadow.

I tried to get some clues from the serial terminal but all I get is a blank, black terminal. (Interestingly executing commands in the LTE Link Monitor is successful ...)

I tried to play a bit with the ports and their options but the only visible result was on the second (not the default for any of the previously (successfully) executed operations) port and it looked like the wrong Baud Rats was given:

Any ideas on how to proceed and how to determine what might be wrong? I've followed the tutorials as closely as possible, yet we're here.

Best regards,

Ivan Popov

[Ivan Popov]

Hi Håkon,

Håkon Alseth said:

Are you 100% certain that the credentials, static client id, and hostname is correct?

Checked them around fifty times - for every of the two devices I registered. Moreover the other types of devices we test with (some Shellys, an M5Stack unit, some Pythons scripts) work under the same conditions: the broker host name is the same for all, and the Client IDs have the same format.

Umm, ... our credentials (mine vs yours) - do they differ only by values? 
I mean, for instance you don't have some extra property that I've missed?

...

Let's say only the values are to problem on my side. Then I register another device in AWS IoT Core to get all values afresh - Client ID, and certificates. Then I provide the new values in the same way:

1. Provision the certificates;
2. Change the configuration and flash the new build on the Thingy.

Then if I continue to have the same problem, what would that mean? That the procedure under which I register the devices towards AWS is somewhat flawed, for instance? Something with the policies probably? 

A lot of questions, I know but at this point anything is possible.

Best regards,

Ivan