Thanks for the input, guys. After doing some targeted searching, I got some info that sent me to a Yahoo help section that ultimately let me type in an abbreviated version of the problem... which sent me to a page listing several problems and one of them was about this confirmation thing. Am gonna try to muddle through it, but it doesn't look hopeful because I don't use a cellphone.
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"Confirm your identity" pop-up message
Description
What to do if you receive a request for sign-in verification. You may see one of these messages:
"You are logging in from a device we don't recognize"
"Please answer your security question"
"We can send a verification code to your listed phone number or alternate email address"
Resolution
The prompt you are receiving is called "Second sign-in verification," and it is designed to protect your account from unauthorized access.
There are several ways to confirm your identity:
Send a code to mobile phone or non-Yahoo! alternate email address:
Go to the Yahoo! sign-in page (
http://login.yahoo.com).
Enter your Yahoo! ID and password, then click Sign In.
You may need to enter the security CAPTCHA code. (If you do not see a randomly generated code, simply proceed to the next step.)
Select Receive Code and enter your non-Yahoo! alternate email address or mobile number.
Note: A code will be sent to the location you entered; make sure you do not navigate away from the page where you entered your alternate email address or mobile number.
Once you receive this code, you will need to enter the code on the page where you entered your alternate email address or mobile number.
You may be required to update your current password.
Note: At this time Yahoo! alternate email cannot be used to confirm your identity. If your alternate email address is a Yahoo! email, please use your mobile number or security question.
Verify your security question:
Go to the Yahoo! sign-in page.
Enter your Yahoo! ID and password, then click Sign In.
You may need to enter the security CAPTCHA code.
Provide the answer for the security question displayed and click Verify Answer.
You may be required to update your current password.
If you do not have a non-Yahoo! alternate email address, valid mobile number, or cannot verify your security question, you may need to Get Help to confirm your identity.
Note: When filling out the form, please select Yahoo! Account under "Product."