If you have received the Facebook Protect scam email below, which claims you must turn it on or else your account will be locked, do not follow the instructions in it because it is being sent by scammers. The scammers' aim is to trick Facebook users into clicking the link or button in it that goes to a phishing website. The phishing website steals account credentials and personal information.
The Facebook Protect Scam Email

If you were tricked by the Facebook Protect scam, please change your password immediately before your account is hijacked.