I lost my @icloud email alias in El Capitan
I use my @icloud.com email address for most of my activity. However, when I updated my Mac to OS X El Capitan, I lost it. It now uses my @me.com address and will not accept me adding my @icloud.com address as an alternative. My iOS devices give me the ability to use either @icloud.com or @me.com addresses but not El Capitan. How do I correct this situation.
iMac, OS X El Capitan (10.11)