Follow these instructions for setting up Yahoo Mail:
If you want to use Yahoo exclusively for your mail, the first thing to do would be to stop forwarding mail in Control Panel (if you have that set up there). Then you configure Yahoo Mail to retrieve your email:
1. Log in your Yahoo Mail.
2. In your Yahoo Mail, you need to click Mail Options – upper right of the screen
3. Under Management - Click “Mail Accounts”.
4. Click “Add”
5. Enter Account Name = this is just a label; use anything you like
6. At bottom left, Click “Continue”
7. Mail Server = mail.your_domain.com
8. Username = email_box_name@your_domain.com
9. Password = your email box password
10. At bottom left, Click “Setup Mail Server”
11. On next screen, highlight the account you just created
12. Click Edit
13. At bottom, remove the checkmark on “Leave mail on POP server”
14. Click “Save Changes”
15. At left, click “Mail” then “Check Mail”
16. You will notice a “Check Other Mail” on the left side and the mail account you created will be listed. Click that and the mail from your account will be downloaded.
17. If you want to create a separate folder for this account, you can create one; and in that edit area where you removed the check mark, there is a spot to specify which folder you want this mail to be downloaded to. If you don’t want a separate folder, the mail for this account will go in your regular mailbox with a colored square on the left side, so you will know that it is mail from that account.
This will solve a full mailbox problem (if there is one at this time) and you won’t have to worry about deleting mail on the server.