Karen has a Windows 10 computer that gives her a message saying her settings are out of date. Leo says Windows won't send that message to her. But her mail program would. And since her mail has disappeared, then it may be that since Verizon is selling Yahoo, AT&T is telling Karen to update her settings. She will want to go into the mail program and delete the account. It won't delete the mail, just the portal to get it. Then Karen will have to re-add it using her login and password. The credentials Karen used to use won't work anymore. Use mail.yahoo.com moving forward. There's also word that AT&T wants users to use a "secure mail key" in order to access their email. Which is a nightmare. What they want her to do is just use the browser email. Here are a few articles to help. Here. And Here.