How to lock camera Y axis

Hi. I have set a camera as a child for my sprite, it is following it from up, looking down. However I only want the cam to follow the sprite and do not “turn” on Y axis.
I have applied a rigidbody to the camera and checked lock Y axis rotation, but it does not have any affect.
So my question is how to override the settings for the cam, in order to stop it turning with the sprite, I want only to follow it on X and Z angles. Thanks!

Instead of childing, you could write a simple follow script, which wont take target y in consideration.

it can be solved in many ways:

1: Assign Script to Camera

function Update(){
     //transform.localEulerAngles.y=0;
    transform.localRotation.y=0; //or any initial value that you want
}

2: you can also assign in parent script

function Update(){
 //transform.GetChild(0).localEulerAngles.y=0;
    transform.GetChild(0).localRotation.y=0;//or any initial value that you want
}

Thank you both for your suggestions. Basically, after I posted this question I figured out another method, before you could answer.

I created an empty object and I set the camera to it as child. And that empty object is constantly set to the x and z position of the sprite while moving, but not the Y axis. So it does not rotate but following the object.