Server disconnects when M95 Sends Data in Burst Mode

Hello There,
We are using the M95 module for our bidirectional communication project. There is no problem in calling and sending sms. However, there are some problems with the server connection.
Device can connect to Server and send heartbeat data every minutes. However, when we initiate a instant connection and transmit data every 1.2 seconds, the device disconnects within 3-4 minutes.
It uses “AT+QIOPEN” command for connection with TCP, IP, Port. And sending data with “AT+QISEND” command.
What could be the cause of the connection error 3-4 minutes after the data burst mode each time, is there such a common situation?

I suggest that it is possible to infer the cause from these status queries

AT+QISTAT //Query the status of TCP connection

AT+QISTATE //Query the status of IP ACCESS connection

AT+QISSTAT //Query the status of Server