Why can't I get all videos to open/play?

[M Hop]

Samsung S4: I recently took some videos at a concert and only a few open/play. The ones that won't open are a grey screen with a lightning bolt thingy. When I touch it "Sorry, this video cannot be played" pops up. What is going on with this?

 

[Rukbat]

If you took the video with the phone, it's likely that the file got corrupted. That could be due to a number of things, but I'd make a wild guess that you saved the videos to the SD card, and it's not a top of the line card.

 

[M Hop]

Is there any way to recover these "lost" videos? I'm not techie at all so any help is greatly appreciated. Thanks!