Process killed by OOM killer
This shows which process was killeddmesg | egrep -i 'killed process'
This will show you which processes are the best candidates to be killeddmesg | egrep -i 'killed process'
oom killer
page allocation failure
You run out of free memory which in combination with too many network services running cause that OOM killer shuts down network in order to prevent chaos in system.
Which at the end would cause kernel panic error and unexpected system restart.