Failing at QMTDISC in one specific module

I have 2 modules, namely EC25-EU, and EC25-E, both PCIe modules. I am sending a list of AT commands through it over LTE, via UART using an ESP32.

the first block of AT commands(setup commands) gets executed easily over both the modules.
The moment the EC-25-E module is asked to send the MQTT command: +QMTDISC command, it fails and shows the error of:

I dont understand why it only happens in the EC25-E version and not the EU version. And what the possible methods to fix it might be.

Hi @Akshat_Taneja
May I ask when you execute the AT+QMTDISC=0 command, is the 0th socket connected? You can use the AT+QISTATE? command to query.