I'm having no luck with this. I deleted the account and tried to put it back. I loaded my wife's yahoo account with no problems. It stopeed working on my ipad too but my wifes works fine. This tellis me it's a yahoo issue. I pay a premium for the yahoo mail with no advertisements. But still the yahoo help *****. They send me a typical message asking how I'm loggin into the mail. Now my calendar is gone from my iphone too, a real pain in the butt. I haven't been able to have Yahoo call me, wish they would. I even got a feedback request from yahoo to see how their support was. This is very frustrating.
Also, I've noticed I get a lot of time out errors when I try to log into my yahoo mail, especially during the afternoon and evening it's only a 20% shot that I can log into my mail. this is with IE or Google chrome on my regular computer at home or at work. There is something going on here, may end up having to switch to Gmail but I've been using this yahoo mail for 13 years.. I'd like to keep it.
Very ****** at yahoo for not being informative about this. I'm sure a lot of people are having this problem.
I did see an alternative to recreate this e-mail account on iPhone using the "Other" option and not the "Yahoo" Option when creating an e-mail account in settings. This did get me my mail back for this account but not my address book which I count on a lot. To do this you need to enter the inbound and outbound mail server when you go this route. incoming mail server imap.mail.yahoo.com and outgoing server smtp.mail.yahoo.com
I created this other account too so the original one is still there for when (or if) yahoo fixes it. but I think I'll have to start transferring all my calendar and address info to G-mail and start using that. What a pain