same thing for me.. just copied yours because I'm back to running a3 since nav server seems to be on the fritz
[09:07:15.919 D] Could not connect to nav server!
[09:07:15.919 D] System.Net.Sockets.SocketException (0x80004005): A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond 188.165.14.154:810
at System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot, SocketAddress socketAddress)
at System.Net.Sockets.Socket.Connect(EndPoint remoteEP)
at System.Net.Sockets.Socket.Connect(IPAddress address, Int32 port)
at Zeta.Navigation.DefaultNavigationProvider.(Vector3 )