In the course of Appx/Clients attaching to a WinAppxD Appx/Server, with 
APPX NET_LOG enabled, the following NET LOG entries can come up.  Here are 
explanations:

        SetProcessWindowStation() returned 1, (err=122)
        CreateDesktop() returned 168 (err=122)

 These aren't errors.  They would be errors if they had returned 0.

        recv() failed, exiting, errno = 10054

 "An existing connection was forcibly closed by the remote host."
                                        (From the MS Win32 API Error Codes)

This can be caused by something in the network (aka an 'assassin') sending a 
RESET packet.  This kills WinAppxD, and therefore all links between 
Appx/Clients and the Appx/Server.  The Appx/Server may or may not be able to 
manually restart, depending on whether something in the network is holding the 
old port open or not.  If the port is being held open, the Appx/Server can't 
grab it again.

That "something in the network" could be routers, modems, or other equipment 
in the network.