When tryng to backuo into iCloud "your last backup couldn't be completed" message appears.

First of all, i was not able to backup my WhatsApp to iCloud, to try to solve this i've checked my backup settings on my iCloud configurations. Once i activated my iCloud backup on iTunes i was able to switch on the backup on iPhone.

With ths setted up, i've tried to backup the iPhone, and the message appeared "your last backup couldn't be completed".

In resume, i can't backup neither my iPhone or my WhatsApp.

I have already tried:

change network;

forced reboot;

reset network settings;