soryy @fm i didn’t answer your question:

i used the public IP address of my server so it shouldn’t have been due to the DNS, without TLS it works

@fm

Hi Felix,

i tried it again with the Mosquitto test server, I have only tried to send the root CA, i.e. Server CA, to the SIM7020, but I always get a Error.

this is my code to send the certificate:

AT+CSETCA=0,1428,1,0,"first 1000 chars"
AT+CSETCA=0,1428,0,0,"next and last 428 chars"

In the Mqtts application note from simcom is a \ r \ n after the ----- BEGIN CERTIFICATE -----, I tried it with and without and tried to limit it to packets with a maximum of 500 characters but it doesn’t want to accept it.

Do you have a example how do you send the certificate to the sim7020 for me?

Thanks for your answer

Hello, everyone,

I have problems connecting to my mqqts server.
I have processed the “MQTTS Application note” from simcom but it does not work.

AT + CMQTTSNEW … always returns an error.
MQTT without TLS works.

I think it’s because of the certificates, server.crt client.crt and client.key but when I upload to the module I always get an ok.

When I connect with a MQTTs client on my PC with the same certificates it works.

Has anyone got this going yet?