Synced video stops with the error:

“Playback has stopped because connection to Plex Media server has been lost” The media is synced to a Samsung tablet that has no data connection and has no network connection while at a remote site. The length of time the video plays varies. Today 32 minutes. Yesterday 60 minutes. This behavior started about a week ago. Both the tablet and my Media server are the latest (as of today) versions. When I bring the tablet home and try again with the local content I get the same error.