I'm apparently using a "nonstandard" version of Yahoo Mail, Web based (using my browser), because I'm prompted at the upper right to "Switch to the Standard Version of Yahoo Mail".

When I click on the "Contacts" tab, so as to access my moderate-length list of contacts, I'm simply taken to a page saying only "Your mail is temporarily unavailable. Please wait a moment and reload the page. Learn more".

EDIT: In addition, when I start to type anything into the "To..." line, Yahoo suggests all manner of random trash email addresses I've never seen before instead of using the contact information I carefully stored there myself years ago.

That's been happening for days now. No contacts list, just a mysterious "Your mail is temporarily unavailable".

Except my mail works fine, provided I don't need any access to my contacts list. I send and receive email all day long. My "Notes" and my Calendar work fine, too. Just... not my contacts.

I'd have posted this in "Help", but I couldn't find any mechanism to do it and nothing already in "Help" addresses anything like this.