Cox Email to Yahoo Mail setup for iOS - SMPT not working

iOS 17.4.1 iPhone 14+ / Mac OS Mac Air

Cox transferred their email addresses to Yahoo mail. I followed all instructions provided but my wife can not send email. Cox and Yahoo have only vague step sheets and zero support options. She gets email but cannot send getting SMTP cannot send. Yahoo settings appear "greyed out". Any fellow Apple faithful been down this road? We are all Apple family and she relies on Mail app on both iPhone and Mac.

I was hoping to give her great Mother's Day gift by letting her be connected again!

History: She has had this email address since 1998 so simply dumping mailbox currently is not option.

Thank you