Don't send security code to the account the user is logging into
Your sign-in process asks for user name, then runs a "I'm not a robot" test, then asks for a security code that it sent to the account I'm trying to log into and NOT MY PHONE. Since your process won't ask for my password, I cannot get into the account to see the verification code.
Your process has the effect of locking out of my account.
I'm sorry to hear you're experiencing this issue! We'd like to help, please send us a private tweet at @YahooCare, message us on Facebook at Yahoo Customer Care or in case you do not have a social media account, our support team is available at help.yahoo.com
Looking forward to your reply!