I receive an email now:
“Sign-in attempt prevented”
Your account is currently not enabled for sign-in from apps that do not meet modern security standards (e.g. older versions of email and calendar apps such as Outlook). As a result, we prevented a sign-in to your Yahoo account.
We strongly recommend that you switch to Yahoo’s apps, such as Yahoo Mail, on desktop and mobile and remove your account from all other less secure apps.
If you still want to use an app that has a less secure sign-in method, go to https://login.yahoo.com/account/security#other-apps and turn on ‘Allow apps that use less secure sign-in’. This is not recommended and can leave your account more vulnerable to compromise.