Keychain WTH (what the heck)

[Numo]

Perhaps I am particularly obtuse today, but I can't figure out how to get Keychain to work.

First I created a new password protected Keychain with a password item for Amazon.com. Then I went to Amazon to reset my Amazon password to match my new Keychain generated password, and quit my browser.

When I went back to Amazon, I expected Keychain to ask me for my Keychain password, and then automatically fill in the new Amazon password, but it didn't - the password field is left blank. What don't I understand here?

[Ken Sp.]

In Safari preferences>AutoFill>Do you have Username and Password selected?

Some sites do not autofill password for security. Amazon has worked for me though.