Some Movies fron Nas stopped playing

I am using Kodi on an Nvidia Shield connected to my QNAP NAS using SMB. Everything was going
well then suddenly some of my movies would not play with the Error Message: “One or more
items failed to play”. When I look in the log, I find several Error Messages: “Unable to look up host (My NAS)”.
Interestingly, when I look at the log after starting some of the movies that DO play it also has some
Error Messages:” Unable to look up host”, but they obviously overcome that. My NAS has a reserved IP
and the movies all play fine using VLC on my computer. I have cleared the Kodi cache on the Shield
and rebooted everything. I have no clue as to why some play and some do not. Ideas?