ANDTech Focus on wireless module and hardware solution for 15 years.
I have managed to properly setup the SIM that i'm using following this sequence AT+CFUN ATEO AT AT+CPIN AT+GMR AT+CSQ AT+COPS AT+CREG AT+CNMP AT+CMEE AT+CGDCONT AT+CGACT (these seem to work properly) MQTT Connection AT+CMQTTSTART (works properly) *AT+CMQTTACCQ=0,"myClient"", "OK"); AT+CMQTTCON=0 (returns +CMQTTCONNECT: 0,0 ) AT+CMQTTKEEPALIVE (Sending command: AT+CMQTTKEEPALIVE=0,30 Received response: ERROR) AT+CMQTTSUBTOPIC=0,20,0 (ERROR) AT+CMQTTSUB=0,20,0 (ERROR)