iCloud App-Specific Passwords Not working with Outlook or other apps

SOLUTION

Hoping someone with the same issue finds this, as the other threads are now locked and I finally solved this for myself.

The issue was / is - that when you select-all & copy your password from the page in Apple, it includes a trailing (or leading) space character; but you can't easily see this when you paste it into the masked password field. So it just seems like the password isn't working.

When you paste the password in, reveal the password to make sure there's no extra space characters anywhere.

Then it should work.