Hello!
Former my relay was connected via a powerline adapter and I often had connection problems.
Then I connected it directlia via a LAN to the router and it worked for 3 days. This morning it was down again since 6 h (no traffic, no flags but the netbook still said that there is a internet connection).
I tried to restart the relay but that didn't work, so I rebooted the hole machine and now the relay is up again (Nick: SMichel).
I tried to check the logs, but that didn't help me. I suppose that the connection problem or whatever will persist.