Yahoo! uses temporary, automatic account locking as a security measure to protect accounts from unauthorized access. Sometimes you can also become temporarily locked out of your own account as a result. I...

You may have received a "Mobile Locked " error on an Android smartphone.

  I Think Someone Has Locked Me out of My Account

What to do if your account has been temporarily locked .

This article explains what may be causing your account to be locked as compromised. There are a couple of...

If you haven't accessed your account in some time. Your account may have been compromised. There were at least three failed login attempts...

As an added security precaution, your account will be temporarily locked from access from new locations if multiple failed login attempts ...

Be assured that this email did come from our Yahoo! Account team, as they are educating all of our users about the benefits of this feature. By adding a mobile number to your accountYahoo! Account

These steps are also helpful if you have forgotten, lost or can't remember your password Too many failed login attempts may result in the account lockingYahoo! Account