Objects stops if it lands in between two colliders

I am building an infinite runner game in which you are a cube that can move left, right, and jump. If I jump and land in between two colliders it stops like if it collided even though all the floors are the same height and there is no space in between them.

I have tried putting physics material with 0 friction to both the cube and the floors, changing the Default Contact Offset to 0.001, and even adding a sphere collider instead of a box collider but that didn't work either.

The Code for the cube is this.

 using UnityEngine;
 using System.Collections;
 
 public class charController : MonoBehaviour {
 
     Rigidbody rig;
     Vector3 vel;
     
     // Use this for initialization
     void Start () {
 
         rig = GetComponent<Rigidbody>();
         Physics.gravity = new Vector3(0,-60,0);
     }
     
     // Update is called once per frame
     void Update () {
 
         vel = rig.velocity;
         vel.z = 10;
 
         if(Input.GetKey(KeyCode.RightArrow)){
             vel.x = 10;
         } else if(Input.GetKey(KeyCode.LeftArrow)){
             vel.x = -10;
         } else {
             vel.x = 0;
         }
 
         if(Input.GetKeyDown(KeyCode.Space)){
             rig.AddForce(new Vector3(0,500,0));
         }
 
         rig.velocity = vel;
 
     }
 }