Node losing connection to Windows file share

My NodeX device regularly gives an access error when I try to play something on my file share.  The share was setup following the instructions published by Bluesound; that went smoothly.  When this error occurs, usually (always?) the desktop computer hosting the file share has a locked screen after inactivity timeout.  Unlocking the screen consistently resolves the access error and I can then proceed to play music from the file share.   I know this doesn't seem to make much sense, but that's what I'm seeing.  Has anyone else experienced anything like this?  Any other ideas?