Yahoo password entry dropdown blank in Apple Mail Mojave

If anyone has any ideas I would appreciate the input...

When I click on my email account in Apple Mail a dropdown appears, with the words "Enter the Password for the account xxxxxxxxx.sbcglobal.net" in the frame at the top. It is blank for several second the it show yahoo!, Sign in using your Yahoo account. and has a place for entering your email.

I enter the user name and click next. It starts out with the same "Enter the Password for the account xxxxxxxxx.sbcglobal.net" in the top frame but the space beneath it stays blank.

Running Mojave on Mac Pro mid 2012 - I know, it's old, but it does what I need until this email problem.

A week ago my yahoo email accounts on all my devices would not sign in. I could sign on in Safari so I searched the discussions and tried different things, finally I deleted and reentered the account in apple mail. iPad and iPhone yahoo email account now work.

On the mac, I tried entering the email in mail, with the above window showing up. When I went into Internet Accounts, click on her account, the same dropdown appeared asking first for the email and the next blank as above.

In the Preferences in Apple mail and clicking on the Accounts tab is shown below.

I opened Mail Connection Doctor and it showed a red offline red dot.

Clicking on server settings and selecting Edit SMPT Server List. Automatically manage connection settings was checked. I unchecked it made sure the port number was correct, added a password - still offline.

I changed Authentication to None and the Mail Connection Doctor showed the status as a Green Dot with Connection to server succeeded: login not required. But Account Information still showed offline as the image above shows.

Today as I was reviewing all I had done, I rechecked Automatically manage connection settings> OK. Email account still offline. Connection doctor shows status as green. Yesterday, though, when I went back to this setting the Doctor shows a red dot. go figure

Thanks for checking this out.