I’m attempting to use the Quectel EC200U-EU module as an MQTT client with SSL.
AT+QMTOPEN=0… is functional, however the error +QMTSTAT: 0,1 occurs after a short period of time (less than the timeout time). This error also occurs immediately after AT+QMTCONN=0…
The SSL certificates and configurations seem to be properly implemented, so I’m not sure why this error is occurring.
Hi @Mayank_Kumaran
Judging from the rejection code, the connection is disconnected or reset by the server. It is necessary to confirm whether the SSL certificate is uploaded correctly, and whether AT+QMTCFG=“ssl” is configured as SSL mode.
The format of the SSL certificates were followed from the Quectel documentation for MQTT setup with SSL, while the AT+QMTCFG=“ssl”,0,1,2 was also used prior to attempting to open a connection.
The list of commands (along with their return messages) that were used are as follows:
AT+QMTCFG=“recv/mode”,1,0,1
OK
AT+QMTCFG=“SSL”,1,1,2
OK
AT+QFLST
+QFLST: “UFS:boot”,15004
+QFLST: “UFS:firm”,243616
+QFLST: “UFS:cacert.pem”,1376
+QFLST: “UFS:clientcert.pem”,1624
+QFLST: “UFS:clientkey.pem”,3324
OK
AT+QSSLCFG=“cacert”,2,“UFS:cacert.pem”
OK
AT+QSSLCFG=“clientcert”,2,“UFS:clientcert.pem”
OK
AT+QSSLCFG=“clientkey”,2,“UFS:clientkey.pem”
OK
AT+QSSLCFG=“seclevel”,2,2
OK
AT+QSSLCFG=“sslversion”,2,0
OK
AT+QSSLCFG=“ciphersuite”,2,0xFFFF
OK
AT+QSSLCFG=“ignorelocaltime”,2,1
OK
AT+QMTOPEN=1,“valid broker”,8883
+QMTOPEN: 1,1 (sometimes this shows as +QMTOPEN: 1,5)
OK
AT+QMTCONN=1,“thing ID”,“username”,“password”
+QMTCONN: 1,1
+QMTSTAT: 1,1
Sorry, a small mistake with the previous description:
AT+QMTOPEN=1,“valid broker”,8883
response: +QMTOPEN: 1,0
Hi @Mayank_Kumaran
Thanks for your information.
From the information provided, it seems that most of the settings are fine, there is one small problem. AT+QSSLCFG=“sslversion”,2,0; the last digit represents the SSL 3.0 protocol, whether it can be changed to 4, all protocols are supported and try.
In addition, can you use the AT+QENG=“SERVINGCELL” command to check whether the current network status is normal?
Best Regards
Lyman
I have done some extra testing, and have solved the issue. However, it seems that my SSL certificate setup is incorrect, which is causing my network to have a connection error. How do I correctly upload the SSL certs?