How do I fix my camera changing rotation when starting the game?

Unity Engine
1

My camera and player object aren’t rotated but when I start the game the camera faces at the ground.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class MouseLook : MonoBehaviour
{
   
    public float mouseSensitivity = 100f;

    public Transform playerBody;

    float xRotation = 0f;
    // Start is called before the first frame update
    void Start()
    {
        Cursor.lockState = CursorLockMode.Locked;
       
    }

    // Update is called once per frame
    void Update()
    {
        float MouseX = Input.GetAxis("Mouse X") * mouseSensitivity * Time.deltaTime;
        float MouseY = Input.GetAxis("Mouse Y") * mouseSensitivity * Time.deltaTime;

        xRotation -= MouseY;
        xRotation = Mathf.Clamp(xRotation, -90f, 90f);

        transform.localRotation = Quaternion.Euler(xRotation, 0f, 0f);

        playerBody.Rotate(Vector3.up * MouseX);

How do I fix this?

2

Have not done anything with mouse movement yet. But could it be because you have mapped the Xrotation to MouseY.?
So when you move the mouse sideways the camera moves on X-axis.

        xRotation -= MouseY;