EC200U SSL connection problem

Technical Subjects
1

Hello, I am using 600 pieces of EC200UEU in a project with firmware version EC200UEUAAR03A20M08_01.300.01.300. There is a problem opening an MQTT SSL connection on port 8883. The response to the command AT+QMTOPEN=0,“2x.xx.xxx.xx9”,8883 is +QMTOPEN=0,5.
Certificate lengths have been checked. The response to the command AT+QIACT? is +QIACT: 1,1,1,“1xx.xx.xx.xx2”.
The connection on port 1883 without SSL works correctly.
When the same certificates are used on the EC200A modem with software version EC200AEUHAR01A12M16_01.001.01.001, the SSL connection is established.
How to solve the problem?

2

pls add

AT+QSSLCFG=“sni”,0,1

then try

3

It does not solve the problem.
Only with the command AT+QSSLCFG=“ignorecertitem”,2,1048575 is the MQTT connection opened on port 8883.