iCloud backup could not be completed
My iPhone 4S comes up with the above message whenever I try to back it up. I have more than enough storage space so I know that's not the problem. I've seen suggestions to delete the previous backup but I'm a bit nervous about doing that. I recently deleted some apps that I never use, maybe that caused the problem? I tried switching off the backup for those apps but nothing seems to work. Even if I try to backup to iTunes on my iMac, it just won't finish.
Any ideas?