The player moves down Y and falls under the floor

please tell me what is the error? I have a player falling down under the floor, the movement on Y is carried out. On the player I have Rigidbody2D configured as usual, set “Linear Drag” to 1 and turned on“Freeze Rotation”. And I also added CapsuleCollider2D.

For the floor, I have enabled BoxCollider2D.

I hung this script on the player:

public class PlayerController : MonoBehaviour
{
    public PlayerState curState;            // current player state

    // values
public float moveSpeed;                 // force applied horizontally when moving
public float flyingSpeed;               // force applied upwards when flying
public bool grounded;                   // is the player currently standing on the ground?
public float stunDuration;              // duration of a stun
private float stunStartTime;            // time that the player was stunned

// components
public Rigidbody2D rig;                 // Rigidbody2D component
public Animator anim;                   // Animator component
public ParticleSystem jetpackParticle;  // ParticleSystem of jetpack

void FixedUpdate ()
{
    grounded = IsGrounded();
    CheckInputs();

    // is the player stunned?
    if(curState == PlayerState.Stunned)
    {
        // has the player been stunned for the duration?
        if(Time.time - stunStartTime >= stunDuration)
        {
            curState = PlayerState.Idle;
        }
    }
}

// checks for user input to control player
void CheckInputs ()
{
    if (curState != PlayerState.Stunned)
    {
        // movement
        Move();

        // flying
        if (Input.GetKey(KeyCode.UpArrow))
            Fly();
        else
            jetpackParticle.Stop();
    }

    // update our current state
    SetState();
}

// sets the player's state
void SetState ()
{
    // don't worry about changing states if the player's stunned
    if (curState != PlayerState.Stunned)
    {
        // idle
        if (rig.velocity.magnitude == 0 && grounded)
            curState = PlayerState.Idle;
        // walking
        if (rig.velocity.x != 0 && grounded)
            curState = PlayerState.Walking;
        // flying
        if (rig.velocity.magnitude != 0 && !grounded)
            curState = PlayerState.Flying;
    }

    // tell the animator we've changed states
    anim.SetInteger("State", (int)curState);
}

// moves the player horizontally
void Move ()
{
    // get horizontal axis (A & D, Left Arrow & Right Arrow)
    float dir = Input.GetAxis("Horizontal");

    // flip player to face the direction they're moving
    if (dir > 0)
        transform.localScale = new Vector3(1, 1, 1);
    else if (dir < 0)
        transform.localScale = new Vector3(-1, 1, 1);

    // set rigidbody horizontal velocity
    rig.velocity = new Vector2(dir * moveSpeed, rig.velocity.y);
}

// adds force upwards to player
void Fly ()
{
    // add force upwards
    rig.AddForce(Vector2.up * flyingSpeed, ForceMode2D.Impulse);

    // play jetpack particle effect
    if (!jetpackParticle.isPlaying)
        jetpackParticle.Play();
}

// called when the player gets stunned
public void Stun ()
{
    curState = PlayerState.Stunned;
    rig.velocity = Vector2.down * 3;
    stunStartTime = Time.time;
    jetpackParticle.Stop();
}

// returns true if player is on ground, false otherwise
bool IsGrounded ()
{
    // shoot a raycast down underneath the player
    RaycastHit2D hit = Physics2D.Raycast(new Vector2(transform.position.x, transform.position.y - 0.85f), Vector2.down, 0.3f);

    // did we hit anything?
    if(hit.collider != null)
    {
        // was it the floor?
        if(hit.collider.CompareTag("Floor"))
        {
            return true;
        }
    }

    return false;
}

// called when the player enters another object's collider
void OnTriggerEnter2D (Collider2D col)
{
    // if the player isn't already stunned, stun them if the object was an obstacle
    if(curState != PlayerState.Stunned)
    {
        if(col.CompareTag("Obstacle"))
        {
            Stun();
        }
    }
}

}