SIM7000E unable to connect - TLS issues?

I’ve been trying to connect to HiveMQ with the SIM7000E for quite some time. I’ve looked through threads about similar SIMCOM devices and still haven’t been able to solve the issue.

  • SNI added
  • Let’s Encrypt root CA downloaded and uploaded to the customer directory
  • SSL-less broker.hivemq.com communication works ok

Not sure about steps below:

  • Should I convert the CA using AT+CSSLCFG=“convert”,2,“isrgrootx1.pem”? Some sources say it’s not necessary
  • Do I need to download additional keys/certificates, like a client certificate? SIM7000 mqtts example uses more keys
  • Is SSL version 1.3 okay?

Steps done:

//SSL config:
AT+CSSLCFG=“convert”,2,“isrgrootx1.pem” ← when executed, returns OK so i guess file is present and has a proper format
AT+CSSLCFG=“sslversion”,1,3
AT+CSSLCFG=“sni”,1,“[id here].s1.eu.hivemq.cloud”
AT+SHSSL=1,“”

//MQ setup:
AT+SMCONF=“URL”,“[id here].s1.eu.hivemq.cloud”,“8883”
AT+SMCONF=“CLIENTID”,“21”
AT+SMCONF=“USERNAME”,“[id]”
AT+SMCONF=“PASSWORD”,“[pass]”

//conn
AT+CNACT=1,“iot.1nce.net
AT+SMCONN << no error, ends with a weird module reset

SIMCOM example below:

//Example of MQTTS Function
AT+CNACT=1,"cmnet" //Open wireless connection //parameter CMNET is

AT+CNACT? //Get local IP

AT+CFSINIT //Init FS AT command

AT+CFSWFILE=3,"ca.crt",0,2110,1000 //After download, sent certificate file through the
serial port.
//2110 is certificate size.
DOWNLOAD
OK
//Send CA file success
AT+CFSWFILE=3,"myclient.crt",0,2110,1000 //Send cert file success
DOWNLOAD
OK
AT+CFSTERM //Free data buffer
OK
AT+SMCONF="URL",117.131.85.139,6001 //Set up server URL
OK
AT+SMCONF="KEEPTIME",60 //Set MQTT time to connect server
OK
AT+CSSLCFG=convert,2,ca.crt //rootCA.pem is CA certificate
OK
AT+CSSLCFG=convert,1,myclient.crt,myclient.
key
//cert.pem is certificate, key.pem is key of cert.pem
OK
AT+SMSSL=1,ca.crt,myclient.crt //Set CA certificate and cert //certificate name
OK
AT+SMCONN
OK
AT+SMSUB="update",1 //Subscription packet
OK
AT+SMPUB="update","5",1,1
>hello //Get data on server
OK
+SMSUB: "update","hello"
AT+SMUNSUB="update" //Unsubscription packet
OK
AT+SMDISC //Disconnect MQTT
OK
AT+CNACT=0 //Disconnect wireless
OK
+APP PDP: DEACTIVE

Hello @anszeju

Welcome to the HiveMQ Community! Check the answers for your question below.

Kind regards,
Diego from HiveMQ Team