> Because Google can unilaterally reject valid credentials if it doesn't feel it's certain it's you. Unbelievably, this even includes rejecting credentials for

> Because Google can unilaterally reject valid credentials if it doesn't feel it's certain it's you. Unbelievably, this even includes rejecting credentials for a non-GMail Google account, even after the user has clicked a link to confirm ownership of the email account the account is associated with. Ask me how I know!