Cannot Access icloud email from any PC or Mobile device

Set up Apple ID using 'name@gmail' which automatically created 'name@icloud' - can log in to iCloud Web Page using either 'email address' and emails sent can be viewed.

Cannot view / retrieve email via PC using Outlook or any Mobile whether IOS or Android - 'set up failed'.

NOTE Same problem with ANY other similar IDs but all is OK when "icloud" is initially used as set up ID.