Your iPhone's mail settings let you customize the email account the iPhone uses for mail. Changes you make to the iPhone's mail settings never synchronize with your computer, so your computer is not affected by any changes. This enables you to set email to work with iPhone independently of email on your computer.

Yahoo! Mail is instantly transferred to iPhone as it arrives at Yahoo!.

Check the iPhone's Mail settings

Choose Settings > Mail > Yahoo! Mail account and confirm that your Yahoo! Mail account information—address and password—has been entered correctly.

Check receiving mail to your Apple iPhone

Go into Yahoo! Mail Inbox, click the refresh icon in the lower left, and confirm that you can receive new Mail messages.

Check sending mail from your Apple iPhone

Go into the Yahoo! Mail Sent folder and confirm that the mail that you are trying to send is there.

Check getting new messages automatically

Your Yahoo! Mail is instantly transferred to iPhone as it arrives at the Yahoo! server. Send a message to your Yahoo! Mail account and look for it on the iPhone.

Check that Yahoo! Mail is set as your default email account

Read the article "How do I set Yahoo! Mail on my iPhone as the default email account?" for details.

Delete the Yahoo! Mail account from the iPhone and re-enter it

Read these articles:

• How do I delete Yahoo! Mail account access on my iPhone?
• How do I set up access to Yahoo! Mail on my iPhone?