I was able to find a solution to this problem on these two threads. To me it looks like poor API documentation. I had to remove device_id from the JSON payload and it worked.
Hello,
I have an Arduino Explore IoT Kit that came with an Arduino MKR Wifi 1010 and Maker IoT carrier. I have been able to go a bit beyond the tutorial and I have 4 variables setup on the Arduino IoT (2 Cloudswitches for Button 0 and 1, and the Temperature and Humidity sensor running). These all work on the IoT dashboard and if I change switches on the Arduino IoT dashboard the Carrier screen updates appropriately. I am also able to read all the values in a custom mobile app through Arduino Io…
ok, that used to be a bug but it was fixed a while back.
I'll report to the Cloud team tomorrow.
VERY IMPORTANT: please remove your boards from that anti-static foam.
That material is conductive and you are basically shorting your board as if you placed it on a piece of metal.
It offers a certain degree of resistance but it's not safe