套接字连接被随机阻塞

Question

I have been working on an Android project, and it has client side and admin side, one or more devices connects to admin using Socket. this app is used for managing orders in a restaurant and its used to order foods and admin can send some data too, for example updating the food list or etc. I am using a heartbeat, sending a request every 5 sec to admin to check if they are connected. the problem is the requests are not being sent every 5 sec all the time. it can randomly change, or sometimes it stops and i can't any errors.

I am using a TP-Link TD-W8960N router and the router has no internet access.

this happens while i move devices from one place to another, i am so confused, at least give me a few to tip to debug it.