My character is falling through the ground

For some reason my fox is falling through through the ground and I can't figure out why. Can someone help? basically, when I press play my character falls through the ground at light speed. If you need any information about my project feel free to ask.

Also, both the ground and character have colliders

Here's my code (sorry for the mess, it's a work in progress): using System.Collections; using System.Collections.Generic; using UnityEngine;

public class Move : MonoBehaviour {

 Rigidbody2D rb2d;
 SpriteRenderer spriterender;
 BoxCollider2D bcol;
 Vector2 ogsize;
 [SerializeField] private LayerMask platformLayerMask;
 [SerializeField] Transform ceilingcheck;
 [SerializeField] Transform crouchpoint;
 [SerializeField] Vector2 sizeocheck = new Vector2(0.0658203f, 0.09773837f);
 bool crouch = false;
 //bool turn = false;


 /*void Flip()
 {
     turn = !turn;

     transform.Rotate(0f, 180f, 0f);
 }*/



 private bool IsGrounded()
 {
     RaycastHit2D raycastHit;

     raycastHit = Physics2D.BoxCast(bcol.bounds.center, sizeocheck, 0f, Vector2.down, 1f, platformLayerMask);
     return raycastHit.collider != null;
 }




 // Start is called before the first frame update
 void Start()
 {

     rb2d = GetComponent<Rigidbody2D>();
     spriterender = GetComponent<SpriteRenderer>();
     bcol = GetComponent<BoxCollider2D>();
     ogsize = new Vector2(bcol.size.x, bcol.size.y);
 }


 // Update is called once per frame
 void FixedUpdate()
 {


     ///////walk//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////




     /*if (Input.GetKey("d") && turn == false || Input.GetKey("right") && turn == false)
     {
         //Flip();
         rb2d.velocity = new Vector2(4, rb2d.velocity.y);
         transform.Rotate(0f, 0f, 0f);
     }

     else if (Input.GetKey("a") && turn == true || Input.GetKey("left") && turn == true)
     {
         //Flip();
         rb2d.velocity = new Vector2(-4, rb2d.velocity.y);
         transform.Rotate(0f, 180f, 0f);
     }

     else
     {
         rb2d.velocity = new Vector2(0, rb2d.velocity.y);
     }*/




     Vector3 movement = new Vector3(Input.GetAxis("Horizontal"), 0f, 0f);
     transform.position += movement * Time.deltaTime * 4f;





     ///////jump//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
     if (IsGrounded() && Input.GetKey("space") || Input.GetKey("up") && IsGrounded())
     {
         rb2d.velocity = new Vector2(rb2d.velocity.x, 17);
     }







     ///////crouch//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
     if (Input.GetKey(KeyCode.LeftControl))
     {
         crouch = true;
     }


     if (crouch == true)
     {
         rb2d.velocity = new Vector2((rb2d.velocity.x) / 2, (rb2d.velocity.y) - 5);
         bcol.offset = new Vector2(crouchpoint.position.x, crouchpoint.position.y);
         bcol.size = new Vector2(bcol.size.x, bcol.size.y / 2);
         Debug.Log("crouc$$anonymous$$ng");
     }

     else if (crouch == false)
     {
         rb2d.velocity = new Vector2(rb2d.velocity.x, rb2d.velocity.y);
         bcol.size = ogsize;
         Debug.Log("standing");
     }


     // redo
     if (Physics2D.OverlapBox(ceilingcheck.position, sizeocheck, platformLayerMask))
     {
         crouch = true;
     }
     else crouch = false;

 }

}