Same here....
After contacting Yahoo Mobile, I was able to make it work again by following their suggestion:
Thank you for writing to Yahoo! Mobile.
I'm sorry that you're currently encountering an issue with Yahoo! Mail
on your Apple iPhone. I'd suggest the following steps to ensure that
your Yahoo! account is set up correctly:
- Delete the Yahoo! ID on currently on your iPhone
- Turn off your iPhone
- Log into your PC and change your password. Many errors care caused by
the way the iPhone encrypts some characters. Please ensure your new
password has no special characters (any character which is not a letter
or a number, such as @ or *). This will reset our registration systems
and ensure that Apple treats your ID as a new connection.
- Turn your iPhone back on
- Set up your Yahoo! Account on your iPhone using the "Yahoo!" option.
Please make sure that you enter your new password when setting up the
account.
- Make sure that your iPhone is not set to Manual Push. To verify this
please take the following steps:
- Open Settings - Select Mail - Select Auto Check - Ensure it is not
set to "manual"
This should trigger a re-sync between your Apple Device and our systems.
If you find that you're encountering issues with registering your
account, or your iPhone is unable to retrieve email just let me know.
Changing my password was the trick.
Now, I am not sure why they would tell me to make sure that Auto Check is NOT set to manual.
What if I have many accounts and don't want to check them all?
Actually, I set it to "manual" and Yahoo Mail gets pushed automatically anyway.
Glad it's working again