Assuming you are playing multiplayer, third person view can be disabled for all clients via the server (it's one of the difficulty options)

That s the interesting thing. In Multiplayer I can, however in editor I can not.

Does your local difficulty setting permit 3rd view?

I am not sure. Where do I look?

Pause menu -> Configure -> Game -> Difficulty (tab) -> 3rd person view

Just on the side, in case anyone is having trouble switching to 3rd person using a laptop keyboard, some (Samsumg) laptops do not have the numpad enter key mapped correctly (it's just a duplicate of the normal enter key), which prevents the user switching to 3rd person mode with Arma 3's default controls. A workaround is to customise the controls.

Thanks ceeeb. That was helpful

Issue closed as obsolete. If you encounter this problem again, please create another ticket. Thank you.