Why won't my videos play on my Nokia

[Android Central Question]

I have a Nokia lumia and recorded music videos at a concert in the USA. On returning to UK I played them once and now they won't play? I'm not very technical so any help in simple terms will be really appreciated.

 

[B. Diddy]

Welcome to Android Central! Do you definitely have a Lumia, or is it one of the more recent Nokia phones running Android? If it's a Lumia, please post here instead: https://forums.windowscentral.com/