BT Mail/Yahoo Mail will not configure
I bought a new mac book Pro with the OS Sierra on it and I managed to get my BT Mail (Yahoo) working after some experimentation.
I then installed the update to OS Sierra 10.12.1 and apart from losing a number of login passwords my Mail was wiped of the machine.
I then tried setting up mail again and I keep getting account login errors from the mail client, yet my BT/Yahoo mail detects that the Mac has successfully logged in!
This is NOT helping my impression of MAC!
I have looked on the communities and the trouble shooting guides but nothing seems to change the basic behaviour.
Trying to set the account up as other fails too as the software thinks the account already exists!
What is going ON!!!!
MacBook Pro with Retina display, iOS 10.1.1, Update 10.12.1