No route to host after the first connection to ssh / nomachine

Question

i've my home pc with enabled SSH and NoMachine (and, also, noip2). When i try to connect to it, it works..but after some minutes, i loose the connection, and, finally, when i retry to connect, i get an error "No route to host"

I don't know if the problem is my router, or my PC configuration. Any suggest is appreciated!

Thanks