Hi, I have a Premium BT email address
I can't send email since 4 April.
The original setting were: imap.mail.yahoo.com and smtp.mail.yahoo.com.
Mail works on webmail. I changed my password yesterday
Those settings will no longer work ( and were never the correct ones to use in the first place) the correct server is mail.btinternet.com for both incoming and outgoing. Use secure ports 993 and 465 with SSL.
Yes, what client are you trying to configure? Authentication in plain text is required.
It will be your email address and password