Why Manageengine NetFlow analyzer stops

Why Manageengine NetFlow analyzer stops

Hello,

I have an evaluation license to test   Manageengine NetFlow analyzer , I've installed it on Ubuntu 

I used this manual 



First how to know and check everything is ok ? I mean ports working and so on ?

Second when I leave the machine for 2 or 3 hours server stop working and I can't reach the web interface ? 


Is there any explanation for this ?


Best Regards ,

                  New to ADSelfService Plus?