I had this problem but it now seems to be resolved. The problem is that since it was resolved email is now unresponsive due to using over 100% of my CPU and I simply cannot use it. Great fix, so now can you fix this issue!!!
Same problem Same lack of support.
Best advice is to go to another email service provider for your emails. I know its a real pain (particularly if you have multiple bt addresses), but the last failure in security was not the first and their failure to answer chat or support (did you get a hyperlink for a freephone, which actually only takes you to the generic problems page and if you select email problems and then password problems, you end up back where you started to begin the loop again?)
I doubt the computer that auto-generated the message was aware of that.
Have you tried Live Chat to resolve the problem?
I also have been unable to login to BT Yahoo web mail since about 19th Feb. The Email Icon on the BT banner takes me to the standard logon on page. If incorrect credentials are entered they are rejected as normal. If teh correct user name and password are entered to page re-directs to https://mg.mail.yahoo.com
This URL may be longer if you have cookies set. That URL never serves a web page no matter how long you leave it to load. This applies regardless of the browser or device used on my BT Broadband connection.
The URL resolves to a number of IP addresses and I can ping each of the IPv4 addresses.
Interestingly if I set up a VPN tunnel to the USA and try the URL it loads no trouble.
I conclude that there is a filter on that domain applied somewhere between BT and the USA.
Until this problem can be fixed I suggest accessing your email using an email client like Outlook for Windows or the mail program on your phone. If you changed your password when the problem first occured remember to use that new password when configuring your email program.
I seem to be affected by this. I use Outlook on my laptop and phone, both asking for password constantly. Only way i can get email at the moment is through web mail which is awful. Please help. I rried using the chat option, ridiculous!!
Have you checked that you have the correct settings in Outlook.
If you are on the BTMail sysyem use the BT ones.
If you are on BTYahoo email system try the Yahoo settings.