# SimCom 7600 error connecting to HiveMQ

**URL:** <https://community.hivemq.com/t/simcom-7600-error-connecting-to-hivemq/3832>\
**Category:** HiveMQ Cloud\
**Created:** [July 10, 2025, 7:19am UTC](https://community.hivemq.com/t/simcom-7600-error-connecting-to-hivemq/3832 "2025-07-10T07:19:14Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![Garrian](https://avatars.discourse-cdn.com/v4/letter/g/7ea924/32.png) [@Garrian](https://community.hivemq.com/u/Garrian)\
**Post date:** [July 10, 2025, 7:19am UTC](https://community.hivemq.com/t/simcom-7600-error-connecting-to-hivemq/3832/1 "2025-07-10T07:19:14Z")

</div>

Hello there,

I have this SimCom 7600 module that I’m trying to connect to my HiveMQ broker.

When I try to connect to MQTT using SSL:// i get error 12, and when i use TCP:// i get error 34.

I really hope anyone can help me out there, it is extremely appeciated 🙂

This is my setup:

```auto
AT+CFUN=1,1
OK

+CIPEVENT: NETWORK CLOSED UNEXPECTEDLY

+CMQTTNONET

+CPIN: READY

SMS DONE

PB DONE
AT+CPIN?
+CPIN: READY

OK
AT+CSQ
+CSQ: 17,99

OK
AT+CREG?
+CREG: 0,1

OK
AT+CGREG?
+CGREG: 0,1

OK
AT+COPS?
+COPS: 1,0,"Telia N Telia N",7

OK
AT+CGDCONT=1,"IP","telia"
OK
AT+CGSOCKCONT=1,"IP","telia"
OK
AT+CGATT=1
OK
AT+NETOPEN
OK

+NETOPEN: 0
AT+IPADDR
+IPADDR: 100.91.206.89

OK
AT+CCLK="25/07/08,09:23:00+02"
OK
AT+CTZR=1
OK
AT+CSSLCFG="sslversion",0,4
OK
AT+CSSLCFG="authmode",0,1
OK
AT+CSSLCFG="cacert",0,"isrgrootx1_begend.pem"
OK
AT+CSSLCFG="enableSNI",0,1
OK
AT+CSSLCFG="ignorelocaltime",0,0
OK
AT+CSSLCFG="negotiatetime",0,120
OK
AT+CMQTTSTART
+CMQTTSTART: 0

OK
AT+CMQTTSSLCFG=0,0
OK
AT+CMQTTACCQ=0,"simClient",1
OK
AT+CMQTTCONNECT=0,"ssl://####.s2.eu.hivemq.cloud:8883",60,1,"####","####"
+CMQTTCONNECT: 0,12

ERROR
AT+CMQTTCONNECT=0,"tcp://####.s2.eu.hivemq.cloud:8883",60,1,"####","####"
OK

+CMQTTCONNECT: 0,34

```

And I’m not 100% sure that the certificate is downloaded correctly (using tera term):  
This is how I did it:

 ![image](https://canada1.discourse-cdn.com/flex035/uploads/hivemq1/original/2X/1/120307d4452550ad20009c5e45c6e95ee9248232.jpeg)  
 ![image](https://canada1.discourse-cdn.com/flex035/uploads/hivemq1/original/2X/9/9a5cb53fef62b37d81df1e5d7ece477d738055c1.png)

---

<div class="post-metadata">

**Author:** ![Daria\_H](https://avatars.discourse-cdn.com/v4/letter/d/dfb087/32.png) [@Daria\_H](https://community.hivemq.com/u/Daria_H)\
**Post date:** [July 10, 2025, 7:42am UTC](https://community.hivemq.com/t/simcom-7600-error-connecting-to-hivemq/3832/2 "2025-07-10T07:42:45Z")

</div>

Hi @Garrian

Please confirm, have you downloaded [https://letsencrypt.org/certs/isrgrootx1.pem](https://letsencrypt.org/certs/isrgrootx1.pem) or from another location?

Tnx,  
Dasha from the HiveMQ Team

---

<div class="post-metadata">

**Author:** ![Garrian](https://avatars.discourse-cdn.com/v4/letter/g/7ea924/32.png) [@Garrian](https://community.hivemq.com/u/Garrian)\
**Post date:** [July 10, 2025, 7:57am UTC](https://community.hivemq.com/t/simcom-7600-error-connecting-to-hivemq/3832/3 "2025-07-10T07:57:22Z")

</div>

Wow, that’s actually a bit embarrassing 😅 I’m not sure where I originally got the certificate from, but after downloading the one you linked — everything works perfectly now.

Thank you so much for the quick and helpful response! This issue has been a bit of a headache lately, so I really appreciate the help. Thanks again! 🙌