And if you are facing this situation, you can do the following two methods to fix the problem.
First method: Do manually to backup your files. Like deleting certain of apps on iCloud backup. And use your device to do so.
And the second is by making a backup of your iPhone's data to computer for the future usage. And here is how to do it.
- Connect iOS devices of yours to computer viaUSB Cable.
- Open iTunes, then scroll down.
- In the summary tab, check the “Backup to this computer” just below the Backup to iCloud.
- Once you checked the option, continue your step with click on Apply for it to back up your iOS device to the computer.
- Look at the iTunes's left side to right-click on your Device and then choose Backup Now.
- Navigate to this: Settings > iCloud to turn Apps off