Troubles exporting from Android app

I've made my first rush project but I can't get it to export.

I'm exporting 4k footage at 1080p using the match framerate setting. I've also tried exporting at full resolution.

When I export, the project renders up to 7%, then it stops (regardless of export resolution) It always stops at this number. When I try rendering a smaller project, it consistently reaches 25% before stopping.

My project is only basic cutting with one fade to black. 4k 25fps footage. 

Any ideas for how to fix this?