To be displayed properly, 360 videos (and photos) need to have 360 photosphere metadata. When editing 360 videos, especially in a non-360 app, the 360 metadata can be omitted or corrupted, making the edited 360 video not recognizable as such in a 360 player or app.
VRFix is an app that enables you to fix the 360 metadata on your mobile device. This facilitates sharing your 360 video without having to use a desktop app. It has been available for Android and is now available for iOS as well.