My TV and system info is in a previous topic:
https://forums.plex.tv/discussion/267639/pbs-channel-unable-to-connect-to-the-content-server
I recorded some shows using the Silicon Dust HDHomeRun Extend. When viewing them on the Samsung TV (and our Vizio as well), the app says the files have no captions or subtitles (I realize they're not the same). When viewing the same content from my iPhone, the subtitles are present and work fine.
Jack