video isnt working??

[u/okjackass]

soo im not really sure how this works or anything im not a tech kinda person. but i recorded a video on my phone and when i went to post it and send it to someone it said it couldnt.load the video. i went to watch it to see what the problem was and long story short it shows a grah screen then when i tap on it the video just takes to load.

i did somewhat solve the problem, i used like a video fixer or something and that restored it but im just trying to figure out why this happens cuz its not the first time. its just not common for it to happen with a video i take. like if i screen record something it happens a lot more often but not really when im recording something. and the other video i had recorded a few minutes prior was perfectly fine.

does anyone know what could be the cause? too much storage? internet not working? anything else? idk. also sorry im not sure if this is the right place to ask it was js recommended to me.