Yahoo cox.net email failures today

I'm having the same problem.  It began this weekend, about the same time I got an email from Yahoo saying "Welcome to your new inbox, ... Welcome to Yahoo Mail
Hello! If you’re receiving this note, it means you’ve completed your Cox email migration. Thank you for taking the steps to get here. We’re confident you’ll love Yahoo Mail and its unique features for organization and productivity."

I configured Thunderbird back during the initial transition from Cox Mail to Yahoo Mail, and it's been working fine until now. 

I'm able to access my emails via the Yahoo website (had to do that just to be able to get here and post this info).