Error message says unable to play media file after uploaded

I specifically bought the WD MyCloud so that I could store photos and videos.  I have only EVER taken videos/photos with my phone5 and used the WD app to upload the content to the WD MyCloud. 

Sometimes after the video or photo is done uploading, it wont play the video file. Or if it’s a photo, it will show up blank.

The message I get if it’s a video is ‘ERROR Uable to play this media fle’.

So my question, is why will some of my videos upload and play, and other times it wont???  I use the same phone, the same app, so I can’t figure out why this is happening and if there is anything I can do to fix it

PLEASE HELP!!!

Welcome to the Community.

Are the files played directly from your computer? What happens if you disconnect your phone from all mobile networks and re-connect it again in order to refresh the app?