EC25 MQTT AT Command for receiving binary data

I used MQTT AT Commands to publish and subcribe data and everything worked fine.
I want to use publish command AT+QMTPUBEX to receive binary data from server.
But it did not work. I always received URC +QMTSTAT: 0, 1 and do not know how to continue.
Let say I want to receive 256 Bytes binary from server.
I send the command AT+QMTPUBEX=0,1,1,0,“topic”,256 after receiving “>” I try to send a
dummy 256 bytes (I don’t know it is correct or not), but the EC25 Module response with +QMTSTAT: 0, 1.
Server side is no problem. I have tested successfully with mqtt paho python script.
The script is like self.publish(“topic”, payload=256, qos=1).
Thank you in advance!

Hi vnn
According to the log, your mqtt connection was disconnected by the server, please execute AT+QMTOPEN to re-establish the server connection. It may be that you have timed out .
Best wishes