Whatsapp-Restore from iCloud is not showing my Backup 10 days back, I've made a backup of Whatsapp and then I uninstalled the application and Signed out of iCloud to give my iPhone 6 to my friend. 

Now when I signed back into iCloud and installed Whatsapp again and gave my same old number, Restore from iCloud saying "No Backup found". 

But I can see the Whatsapp backup of 540MB in Settings> iCloud> Manage Storage> Backups. It has messages from more than a year that I'm saving it.

I never came across this situation earlier while reinstalling. 

I've enough storage space to restore and I tried with connecting to the Wi-Fi and Mobile data.

My current iOS version is 10.3.1 from more than a month.

Any help or suggestion to get back my backup would be highly appreciated. what should I do now?

Thanks million
You need to change your phone name from Settings > general > About > Name and make sure the new iPhone's name as same as before. After reboot/restart WhatsApp you will able to find the backup.