Q: My iphone 5 won't backup from icloud since 19 Sep - why?

Hello rutha22,

It sounds like iCloud backup just will not complete at all, not even manually. I remember having a very similar issue not too long ago, and I resolved it by turning off iCloud Backup here first:

How to back up your devices using iCloud or iTunes

1. Connect your device to a Wi-Fi network.
2. In iOS 8 or later, tap Settings > iCloud > Backup.

Then quitting the Settings App:

Force an app to close in iOS

1. Press the Home button two times quickly. You'll see small previews of your recently used apps.
2. Swipe left to find the app you want to close.
3. Swipe up on the app's preview to close it.

 
When you have done that restart the device, turn on iCloud backup and test the issue again:

iOS: Turning off and on (restarting) and resetting
 
 

If you continue to have issues making the backup, I would suggest looking at the information in this article for additional assistance:

Get help backing up your device in iCloud

1. Make sure you're connected to the Internet with Wi-Fi.  
2. If possible, try connecting to a different Wi-Fi network.
3. See if you have enough iCloud storage for your backup, and get more storage if you need it.
4. If you need more help, contact Apple Support.

Thank you for using Apple Support Communities.