Still cannot create iCloud mail alias

It is instructive to find the earliest posts on the Internet about a particular problem: the "can not create an alias at this time" error message first appeared in 2013 on discussion boards. So here it is, 7 years later, and my humble effort to create an alias was unsuccessful after relogin, different browser and clearing cache.

The iCloud User Guide is blissfully unaware of this potential problem.

If anyone has a real working solution, I would be happy to hear it. Thanks.