App keeps crashing when trying to export

I just finished making this video for my grandmother's funeral and I'm trying to export it. It keeps on crashing when it starts processing at 5%. I closed the app and reopened it, I shut my phone down and started it back up. I updated my phone to the latest software. Nothing seems to work, I'm getting the same results. This is really starting to become frustrating, I'm on limited time to get this video sent out and the app just won't do it!!! Does anyone please know how to fix this issue? I've had this app for 3yrs and this never happened before.