I have a Lilygo SIM7600E-H module (LE11B13SIM7600M22) and want to send data over MQTT. I cannot get this to work however. The AT command manual states that first the MQTT services has to bes tarted with command AT+CMQTTSTART. This does not work for me though, I always get ERROR in return. The only MQTT related command that ever returned something ('OK') was AT+CMQTTREL=1. I've only seen that once, so far any MQTT command always gives me ERROR.

The SIM card seems to work fine as +CPSI gives me the result LTE,Online,204-08,0x840A,22323469,70,EUTRAN-BAND20,6400,3,3,-157,-1113,-790,8'.

What sequence do I have to execute in order to send something with MQTT?