Error stating "cannot backup to cloud" on new iPhone 5s.

I just set my mom up on a new phone (5s 16 gig newest ios9) and she keeps getting a error message popping up that says it cannot backup to the cloud. We have never used the cloud before but had to so we could move all of her info from her 4s to the new phone. I have not set up the backup on any type of schedule or anything so we weren't even trying to back it up.