How to delete autocomplete email addresses?

[AndyCalling]

This can't be as hard as I'm making it. Once I've typed an incorrect email address into W10's new email app how do I stop it trying to persuade me to make the same mistake over and over again? The email app seems to want to offer the error address every time I start to type an address into a new email.

In W8 and previous versions there was a simple registry entry to tweak. What's the process now? I have searched for the error address in the registry and can't find it at all.

Can you tell me the secret?