Why has plex suddenly stopped playing many items (there was a problem playing this item)

Moveis and TV-shows thats ive watched more than 20 times have suddenly stopped playing. For example. I have Inside Out. My kids have watched it many times through the fire stick, iphone app, android app, and from the computer. This is happening to many videos from avi, mkv, mp4. I have verified im on latest version of plex server Version 0.9.16.3 and android/apple/amazon app. Normally if playback fails on any of the devices but now i cant even play it through the web browser on my pc(which is the server). If i go directly to the file i can play it with vlc, divix player, or windows media player. I have rebooted server and I cant thing of anything else to try. I know for a fact we watched Descendants yesterday on multiple devices and now cant watch them on any. Please help.

Posting your server logs would help diagnose the issue.
Beyond that, I would look at the available free HDD space you have available to the transcode temp folder as plex now checks to make sure there is enough free space, if not it will not transcode them media.

REF: https://support.plex.tv/hc/en-us/articles/200250347-Transcoder

This is the weirdest thing. Now one of the movies is magically playing but others still will not. I tried more than 10 times to get descendants to play on multiple devices and it wouldnt. I tried starting from the beginning and where it left off and neither worked. Now this time it played. However other movies/tv shows are still acting this way.

To get descendatns to play i said to play trailer then stopped the trailer and then tried playing the movie and it worked. i tried that on inside out and its still failing.

Now most of the stuff is playing that wouldnt play for the last 3 hours. Im so confused as to what the problem might have been.

now that same movie is not playing again.

@hthighway said:
Posting your server logs would help diagnose the issue.
Beyond that, I would look at the available free HDD space you have available to the transcode temp folder as plex now checks to make sure there is enough free space, if not it will not transcode them media.

REF: https://support.plex.tv/hc/en-us/articles/200250347-Transcoder

You sir are a freaking genius. Hard drive space was low on the program files drive. Thank you so much i was pulling out my hair.