Smartphone Questions? Ask A Smartphone Technician for Answers
Hello I am Samuel. I would suggest removing the account completely from the phone. Download the Yahoo mail app and sign in with that. Do you need help performing any portion of this?
To remove a yahoo account go to your phone's main settings app, then go to accounts & sync. Tap on the account you wish to delete, and then press menu thenremove account.
Did this help you at all?