This article provides the steps needed to complete verification if you have used another Yahoo! email address as an alternate email address for your account and are receiving an error.

A browser is only capable of holding one cookie and cannot log into 2 Yahoo! accounts simultaneously.

You will receive this notice if you're trying to verify another Yahoo! account as your alternate email address.

To verify your alternate email address:

1. Return to the email account where we issued the alternate email address verification link.
2. Highlight the verification URL and either right-click with your mouse and select Copy, or press Ctrl+C on your keyboard to copy the URL.
3. Click Sign Out at the top of the page.
4. In your Web browser's address barEx: http://mail.yahoo.com, either right-click with your mouse and select Paste, or press Ctrl+V on your keyboard to paste the verification link into the address bar, then press Enter.
5. Sign in with your alternate email address and password.

Your alternate email address should now be verified.