iphone 6s plus not getting backup to icloud on ios 9.2
I have bought a new iphone 6s plus on November, however it is not getting backed up to icloud on ios 9.2, but am able to take back on my computer using itunes. I was having iphone 4s prior to this and it was working fine, not sure what is going wrong here. Please advise.
iPhone 6s Plus, iOS 9.2, Icloud Back up is not happening