Why can't I access my att.net (Yahoo) email from my Samsung Galaxy S6 phone?

[AC Question]

When I try to access my email my Samsung Galaxy S6 keeps saying my server changed the password and requests new password. I haven't changed my password. I entered my second email address on att.net and it worked once or twice and then I got the same message on it as well. How can I fix this?

 

[ManiacJoe]

Which email app are you using?
Yahoo really does not like any other email apps except their own due to the last few hacks of the Yahoo servers.

Using a web browser, go to your Yahoo account and check the security settings.
You want to find the stuff about "legacy" apps or something like that.