I have my iCloud mail account on the stock email app on my Samsung Galaxy S4. From a couple of weeks, however, it doesn't download any new email. As of today (27/08), the oldest one that appear is on the 10/08, and meanwhile I've received 6 emails but noone of them show up.
I'm sure it's not a credenial issue as I can easily send emails from the app and they get delivered.
My synchronization options are OK (it's set for every 15 minutes), and even if I manually update it still doesn't shown any new message, even though it says:
Last update: Today 14:00