After almost a year of great service, OUTLOOK.COM is now unable to access my domain account servers at Yahoo Small Business since August 1st.  This is a paid web hosting Yahoo service.  The servers are pop/smtp.bizmail.yahoo.com.  The error generated within OUTLOOK.COM is:

 "We couldn't sign in to your POP3 server. Please make sure your username and password are correct."

My user name and password are correct as evidenced by everything but OUTLOOK.COM being fully able to get my mail from these servers.  This includes my Outlook 2013 client on a W8 desktop and W8 Laptop, Windows Mail (from Windows 8), Windows Phone 8 mail account, SurfacePro (using both the client and the Mail app).  And, all the above use the same settings I've used with OUTLOOK.COM.

I've had quite literally a hundred suggestions from Microsoft sources on things to check, delete and re-add the account, change ports, etc.  The latest, from a "Level 2" tech from a ticket raised on www.support.microsoft.com is that "Microsoft servers and Yahoo servers are simply not going to be able to reliably communicate."

Can this be verified as Microsoft's position?  If so, then I feel like I've done the wrong thing investing so heavily in Microsoft Windows 8 products and I'll need to completely change all my OS, Mail and Phone schemes.  I'm begging for a solution and I would pay (in fact I have paid and they had to refund my money because what I bought doesn't cover the "free" OUTLOOK.COM service).

Help!

P.