we try to test the connection to the CoT with a ublox-Evalkit with SARA-N200. We do the sample session “NB-IOT Access and Cloud of Things” (from page eigth) shown in the Quick Start Guide. Up to the ping into the cloud everything seems to work without any problems. The next step (sending data to the cloud) does not show the expected CONNACK (hex: 030500) but hex 0218 instead, which probably means DISCONNECT. A log of the command sequence is attached. The device in question was previously registered in the cloud using a csv file (see attachment). The procedure “Mass registration for NB-IoT devices” (see page 67 of the user manual “Cloud of Things”) was used.
What could be the problem that prevents data exchange with the cloud?