Hi Kitti,
Thanks for spending the time to reach out to us. I'll do my best to help you out.
The "Confirm your identity" prompt is one of the many security features we've put in place to ensure that you're the only one who can access your account.
We've updated your account information by adding your alternate email address or mobile number. You can now use this information to get past the "Confirm your identity" prompt.
Important - Keep the "Confirm your identity: enter verification code" box open. If you close the box, you'll have to start over again by signing in to your Yahoo account.
Verify account by receiving a code
Click Receive code.
Select By phone or By email.
Click Receive code again.
Check your email or mobile number, and enter the code in the "Verification code" box.
Click Verify code.
Verify account by answering the security questions
Enter the answer to the security question displayed.
Click Verify Answer.
Once you're back into your account, we suggest that you verify your alternate email address or mobile number.
You can find some extra information about this (and other Yahoo products) through Yahoo Help Central.
If you have any other issues, definitely let me know.
Thanks,
Rachel