Having setup raspberry pi to run as a server, I started noticing that terminating ssh connection will kill the processes I started in it. Some of these were to just serve directory over wifi for easy photo library. This time the difference was that I was tried to kick start server thru my phone (termux) & as soon as I closed the app or moved out of network, server on rpi would die.
In past I just started a tmux session and started server in that. The good thing is that tmux will hang around even if I terminate ssh connection.
But more importantly, tmux works well and here is a very good overview of how unix/linux works with respect to current problem.