It came back the next day - obviously nothing wrong with hackers or transfer to BTMAIL.
I looked on the BT site, and there's a trail of woe from people complaining its been happening for two years, they still are getting cut off from their email, and BT India is useless.
However, there's one post from someone, who was told a workaround ,by a BT UK adviser. Seems if you go to yahoo login, and login, you can still read your meails when this happens. Its going from the BT site that t the attaempt fails.
So they have moved people from btyahoo's login , to their own login on BT dot com, and now have to tell poeple to go to yahoo as their own site isn't reliable . Difficult to believe how anyone could make such a mess.
https://community.bt.com/t5/Email/ya...BT/td-p/831184