Not receiving account Key

Hello,
I want to explain more about the problem, I've email on yahoo this email I can't access more WHY, because the yahoo mail not using more the password and instead of that by the Account Key for using the phone to access the mail, now I can't access to my mail (never by this way) because, I'm not received the ACCOUNT KEY perhaps missing on my phone and I didn't Note it. I want to go back to use my password to access my mail.