[PS4] There was a problem playing this item

Hi there,

So I was watching Lord Of The Rings: Fellowship of The Ring, which has .mkv files (cd1 and cd2). I watched cd1 properly, subtitles worked as it should. However, when Plex started playing cd2 (automatically when cd1 finished), I didn’t see any subtitles. When I went to the subtitle settings, it was set to Dutch.
I tried to change them to English, but I got the error: “There was a problem playing this item”. I tried things like setting subtitles to none, and then to any language but nope… I also restarted the Plex app on PS4, still the same message.
I have 300GB of free disk space, so that can’t be the problem.

I also looked at the log files, but I can’t find the problem. The only message about subtitles I found is:
Jul 13, 2016 01:32:07.105 [6668] WARN - [ui-ps4-ps4] [MDE] Direct play failed; asked to always burn subtitles

I included the log files of the time when I was watching and trying to change the subtitles. Log file with .3. is the log file with the warning about ‘Direct play failed’.