I have a first install of the opensource 2.3 version with demo data. Everything seems to be working in the public facing pages, but I can't login as Admin. The demo customer login is fine.
I don't get anything in the error logs, the message returned is "The account sign-in was incorrect or your account is disabled temporarily. Please wait and try again later."
The user isn't locked.
It seems to blow up in the function at line 568 of
vendor/magento/module-customer/Model/AccountManagement.php
function authenticate($username, $password)
But i'm not sure how to follow it after that.