Can't find Yahoo mail setting to "Allow apps that use less secure sign in".
Since noon on 2/1, I've been unable to download POP3 from Yahoo/AT&T using my Thunderbird 45.7.1 mail client. I've tried changing servers and settings to no avail. The mail.yahoo.com web interface works fine.
The one possible solution I've been unable to try is to enable "Allow apps that use less secure sign in" in Yahoo mail settings.
From https://help.yahoo.com/kb/SLN27791.html ("Ways to securely access Yahoo Mail"), I click on the link on "Go to your "Account security" settings" (https://login.yahoo.com/account/security#less-secure-apps), which redirects to https://edit.yahoo.com/config/eval_profile?dnr=1#less-secure-apps. On this page (which looks like a legacy interface for Profile Information), there is nothing that says "Allow apps that use less secure sign in."
Similarly, clicking on the gear on my Yahoo mail page does not offer an option for "Account Security". (The only options are for Themes, Settings, Email Support, Keyboard Shortcuts, Privacy, Legal, & About our Ads. Under Settings, the only sections are Viewing email, Writing email, Accounts, Vacation Response, Filters, Security, and Blocked Addresses. There is nothing to allow access to less secure apps under the Accounts or Security sections.)
(For that matter, I also can't find an option to set two-factor authentication, which should be on the same settings page.)
There are a number of recent posts that indicate people have been used the "Allow apps that use less secure sign in" option. Why can't I find it under my account?