UNREAL app crashing randomly

Hi all, we were tasked to create an app to simulate an underwater environment with randomised fishes and mermaids swimming about, 6 units of PC connects to the server to run the app to sync fish positions. Unfortunately the app keeps crashing ON SITE for no apparent reason. Back in office it runs fine and well for long periods of time. The only different in office environment vs client, is that we have better machines with higher ram/ better gfx cards, and has UE itself installed and maybe different network switch/ cables.

Would appreciate (even willing to pay) for some help on this 8(…

Log files here: www.dreamchasers-interactive.com/31st_October.zip