In some instances, iCloud “Back Up Now” option (Settings > iCloud > Storage & Backup) on your iPhone, iPad, or iPod touch may appear “grayed out” or dim. If this happens, you will not be able to back up your device manually by choosing Back Up Now.
If you are having this problem, follow these steps to fix the issue. Note that after performing each step, check to see if the problem has been resolved.
1. Make sure that airplane mode is off (Settings > Airplane Mode) because you must have a wi-Fi connection to start your backup.
2. Make sure that is connected to Wi-Fi.
3. if “Restrictions” turned on in Settings > General > Restrictions; tap Settings > General > Restrictions > Accounts and set this to Allow Changes.
4. Reset the network settings (Settings > General > Reset > Reset Network Settings).
5. Update your iOS device (Reset the network settings by tapping Settings > General > Reset > Reset Network Settings)
6. Make sure that you have enough memory left on your phone. Tap Settings > General > About > Available, and make sure that you have at least 50MB’s available.