Syncing not working.

Hello,

I paid for a plex pass for the specific reason that I wanted to sync movies to an Android Fire for use on trips in the car or plane. This is so my son has something to do on long trips. This is not working - it allows me to sync but then when trying to play the content while offline it complains about not being able to contact the server where the file is located. Well it should be local, not on the server. This feature is USELESS if this does not work offline. How do I fix this? I have a really long flight coming up and I’m going to have to just use handbrake and some movie player because I can’t trust Plex to do its job.