Video taken iPhone using Swift not working on Android

I am making a mobile app that has an Android and iPhone version. The app allows for the recording of video which gets pushed up to a server and then can get pulled down and viewed by both the iPhone and Android application. The video is getting saved as an mp4 before it gets pushed up to the server. The videos works on the iPhone and on my Windows computer when I use VLC, but when I put the videos on my Samsung Android device they will not play properly.

Has anyone else run into an issue with cross platform video like this before? I am open to making changes anywhere in the Swift that uploads it or the Android Java code that accesses it.