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]

Oh, I'm sorry!

I probably had to share that information earlier (I guess I forgot about this because it was covered in a previous ticket) - there is not LTE-M coverage in the country. There is maybe like one and a half (the second one is not official) provision of NB-IoT from the local operators. So we used that in order to register the Thingy in the nRFCloud initially (we used 1nce, because iBasis provided only LTE-M here).

So, with that in the context, here are two more screenshots:

and 

which I hope provide some relevant information. On the second one the UART indicator in the top-left corner constantly changes between yellow and red.

And no - there no any other logs in the console over time. I really hoped to see something like this already.

Regards,

Ivan