Reject unknown sign-in attempts
When two-factor authentication is turned on and a sign-in attempt occurs on a new device, you get a notification on your other trusted devices. The notification includes a map that shows the new device’s location. This notification can appear on any trusted iPhone, iPad, or Mac.
The location of the sign-in attempt is approximate, based on the IP address or network that the device is currently using, rather than on the exact location of the device.
If you see a notification that your Apple Account is being used to sign in on a new device you don’t recognize, select Don’t Allow to block the sign-in attempt.
IMPORTANT: You may want to capture a screenshot of the notification before dismissing it. See Document suspicious or harmful activity.
If you think your Apple Account might be compromised, see Keep your Apple Account secure and remove unknown devices.