Did you change the password for that other mail account? If so, did you also update your Yahoo! Mail account? Yahoo! Mail doesn't know if you have a new password unless you enter it. So, editing this information in your Yahoo! Mail account settings should correct the problem. And it's simple!

To do it:

1. Log in to your Yahoo! Mail account.
2. Click Options in the upper-right corner of your Mail page and select Mail Options.
3. From the list on the left, click Accounts
.
4. Click Add or edit an account.
5. Click the account once to highlight it. Then click Edit.
6. Under Receiving Mail, enter the new password in the field provided.
7. Click Save Changes—now with two locations, in the upper-left and lower-left corners.

Note: If you update this setting and still have trouble, contact your Internet Service Provider or your work or school's Network Administrator to see if too many password attempts tripped a switch that temporarily blocks your account.