Backing up our device such as iPhone is a necessary work in our daily life. If you don't backup your iPhone, there will not be backup files for you to restore back to your iPhone once you lose some important data on your device. However, there are times when iPhone backup could not be completed. And once that occurs, don't worry, there are solutions to this.
iPhone backup could not be completed
Solution 1: Backup iPhone to computer via iTunes (Make sure you have a backup in case something goes wrong)
Solution 2: Log out off iCloud and Log back in (iCloud could be the primary cause, so check it out to see if you can fix it there)
Solution 3: Reset Network Settings (Your device might not be connected to network properly)
Solution 4: Change to New WiFi network (Check if there is something wrong with your network and try another network)
Solution 5: Delete old backup from iCloud (You have only 5 GB of free iCloud storage, and once the backup exceeds 5 GB, it won’t backup the iPhone)
Solution 6: Restore your iPhone (Restoring your iPhone will give you a brand-new, clean device from the start)
Above solutions should also fix 'iCloud the last backup could not be completed' issue. In addition, you can also choose to backup your iPhone to the computer instead of iCloud. You can use iTunes or a third-party backup app to do this.
Customer support service by UserEcho