I Have yahoo plus and I can check my email via outlook 2013 widows live mail my Rt tablet and thunder bird so I know the issue is not with yahoo.

When I add the account it tells me that it is a password issue or I don't have yahoo plus 

The settings are entered correctly I also tried to I'm port from window live error same issue  I have emptied all folders junk inbox and sent mail.

I also tried to forward from yahoo.com but the alias never gets the test email more does get conformation emails from Facebook when tiring to add the new address I also tried verify my account by sms but it will only allow me to put in 4 of the eight numbers