If you get an error when trying to create your video on the iPhone app, in most cases it is related to fetching your footage from iCloud.
This could be just a temporary technical issue communicating with Apple's iCloud Photo Library service. However, it could also mean that your iPhone deleted the full-size version of the footage once it was uploaded to iCloud to optimize your device's storage. Read more from Apple Support at 'Set up and use iCloud Photos.'
You can verify that on your device's settings.
On your iOS device:
- Select Settings on your iOS device.
- Select your name at the top of the settings screen to open your Apple ID settings.
- Select iCloud to open your iCloud settings.
- Select Photos.
If the Sync this iPhone/iPad option is selected, it means that your full-resolution photos and videos are automatically stored on iCloud and that a smaller, lower-quality file is kept on your iOS device.
You can work around this by:
- Download the footage you'd like to use in your video from iCloud to your device so you have the full version copy of it locally. This will take up more storage on your iOS device. Learn how from Apple Support at Download iCloud photos and videos.
- Download the original footage from iCloud onto a desktop computer or laptop and create a video using the desktop editor.
If you are still facing trouble with error messages when trying to create or save your video on your iOS device, please Contact Support.