prueba a cambiar el .es por .com
osea:
entrante: pop.mail.yahoo.com
saliente: smtp.mail.yahoo.com
si tienes una cuenta premium de esas:
Yahoo Plus Incoming Mail Server (POP3) - plus.pop.mail.yahoo.com (SSL enabled, port 995)
Yahoo Plus Outgoing Mail Server (SMTP) - plus.smtp.mail.yahoo.com (SSL enabled, port 465, use authentication)
y si no, purbea a configurar la cuenta como IMAP, que me parece que es lo que usa el iphone:
YAHOO IMAP
Username: [email protected] (enter your complete yahoo email address)
Password: enter your yahoo password
IMAP Server: imap.mail.yahoo.com
Port: 143
Security Type: None
IMAP Path Prefix: leave blank
5. Touch next to continue to SMTP Server Settings and enter the details as follows:
SMTP: smtp.mobile.mail.yahoo.com
Port: 587
Security Type: None (Checkmark “required sign-in”)
Username: [email protected] (enter your complete yahoo email address again)
Password: enter your yahoo email password again
6. Touch Next
7. Fill out your personal information (Name etc.)