TCP connection unstable

We are using the BG95 to send data to a tcp server. The modem sends data with AT+QISEND=0 for some time then after 3-4 minutes the sockets connection is at state “closing”, why is that? We never call to close the socket.

Hi
Have you checked network service is good? and the server side also need to check if there any timeout for connection without data transimission.