My neighbour access to my apple tv!

The best way is to have Airplay turned off completely, while not using it. I'm surrounded by 4 extra Apple TV's and my neighbours will pick the wrong one all the time. That means my viewing of movies will be interrupted, or even worse: when I'm not at home, my TV will still turn on to show the password prompt and then not turn itself off for hours...

It's a huge mess and I can't believe Apple is not fixing this flaw.

You could be encountering peer to peer AirPlay which allows others that are in close proximity to AirPlay to an Apple TV without having to be logged onto your wifi network. In flats and apartments this can also include neighbours.

Whilst it won’t stop others trying to AirPlay to your Apple TV, to cover the possibility that it may be being done by accident, you may wish to think whether the name of your Apple TV is sufficient to deter accidentally trying to connect. You can change the name of your Apple TV at Settings > General > About > Name. You can also set your AirPlay security settings to avoid those you don’t want being able to AirPlay to your Apple TV or ensure that the message you have seen stops.

There are two types of password protection for AirPlay.

The first is an on-screen passcode, in which the Apple TV will display a four number password on screen, which you must enter into your mobile device before AirPlay can be enabled. This is typically to ensure that users are in the room where the TV is, before enabling AirPlay. This typically protects against disruptive behaviour from someone somewhere else while someone is trying to use AirPlay.

The second is a hidden password password which needs to be remembered by all users who will have access to AirPlay, unless you share this password with others. This method doesn’t lend itself well to use by guests unless you tell them your password but it does mean that accidental attempts from others don’t disturb you.

You can turn either type of protection on or off by navigating to Settings > AirPlay.

Hi HelloAndreas. It may help some to use a distinctive name for your Apple TV.

You can report the problem to Apple at this link: Feedback - Apple TV - Apple.

suppose it could be 2 things

being that he is not connected to your wifi network

1. Bluetooth I would check if that can be disabled in your appletv settings or if it can be set to require a passcode

2. peer to peer network again I would check the settings if you can disable it