iCloud's outgoing message server has disappeared after upgrading to El Captain

Mail->Preferences->Accounts: if there is no iCloud at all add it with the + sign. If there is no smtp filled in fill in iCloud nothing else. After that in the account settings, click Advanced and check "automatically check...". save and get going

Indeed, this works. It's still amazing how bad Apple's software products have become. Fancy and shiny devices are not enough. Either Apple does something about its software or it will go under.

This does not really contribute. We try to help solve issues here not redesign products...

I have never seen a technical product that does everything every individual expects from it.

Have a nice day.