Skips off block when landing

So, while back I created a game which is voxel based, and it is similar to minecraft. But like i said, the odd thing is since the beginning I slip off a block when I land to the little part of it. and I think it ruins the gameplay all together, So I want to fix that.do you guys know what the problem is? here is the code for the player movement

using UnityEngine; using System.Collections;

public class CharacterMotor : MonoBehaviour {

 private CharacterCollider character;
 
 private CharacterMotorMoving motorMoving = new CharacterMotorMoving();
 private CharacterMotorJumping motorJumping = new CharacterMotorJumping();
 
 [System.NonSerialized]
 public Vector3 inputMoveDirection = Vector3.zero;
 
 [System.NonSerialized]
 public bool inputJump = false;
 
 [System.NonSerialized]
 public bool holdingInputJump = false;
 
 void Awake() {
     character = GetComponent<CharacterCollider>();
 }
 
 
 void FixedUpdate() {
     Vector3 velocity = character.GetDeltaPosition() / Time.deltaTime;
     motorMoving.ApplyMoving(this, ref velocity);
     motorMoving.ApplyGravity(this, ref velocity);
     motorJumping.ApplyJumping(this, ref velocity);
     
     character.Move( velocity*Time.deltaTime );
 }
 
 public bool IsGrounded() {
     return character.IsGrounded();
 }
 

}

class CharacterMotorMoving { // максимаьные скорости движения private const float moveSpeed = 4f;

 // максимальное изменение скорости за секунду
 private const float maxGroundAcceleration = 20;
 private const float maxAirAcceleration = 1;

 // гравитация
 public const float gravity = 17;
 // максимальная скорость падения
 private const float maxFallSpeed = 15;
 
 public void ApplyMoving(CharacterMotor motor, ref Vector3 velocity) {
     Vector3 desiredVelocity = motor.inputMoveDirection * moveSpeed;
     Vector3 delta = desiredVelocity - new Vector3(velocity.x, 0, velocity.z);
     float maxDelta = GetMaxAcceleration(motor.IsGrounded()) * Time.deltaTime;
     velocity += Vector3.ClampMagnitude(delta, maxDelta);
 }
 
 public void ApplyGravity(CharacterMotor motor, ref Vector3 velocity) {
     velocity.y -= gravity * Time.deltaTime;
     velocity.y = Mathf.Max(velocity.y, -maxFallSpeed);
     if(motor.IsGrounded()) velocity.y = Mathf.Min(velocity.y, 0);
 }
 
 private static float GetMaxAcceleration(bool grounded) {
     if(grounded) return maxGroundAcceleration;
     return maxAirAcceleration;
 }
 

}

class CharacterMotorJumping {

 private const float baseHeight = 1.0f;
 private const float extraHeight = 1.4f;
 
 private bool jumping = false;
 private float jumpStartTime;
 
 public void ApplyJumping(CharacterMotor motor, ref Vector3 velocity) {
     if (motor.IsGrounded() && !jumping && motor.inputJump) {
         jumping = true;
         jumpStartTime = Time.time;
         
         // Apply the jumping force to the velocity. Cancel any vertical velocity first.
         velocity.y = 0;
         velocity += Vector3.up * CalculateJumpVerticalSpeed(baseHeight);
         return;
     }
     if (jumping && motor.holdingInputJump) {
         // увеличиваем высоту прыжка
         if (Time.time < jumpStartTime + extraHeight / CalculateJumpVerticalSpeed(baseHeight)) {
             velocity += Vector3.up * CharacterMotorMoving.gravity * Time.deltaTime;
         }
     }
     if(motor.IsGrounded() || velocity.y <= 0) {
         jumping = false;
     }
 }
 
 
 private static float CalculateJumpVerticalSpeed(float targetJumpHeight) {
     // From the jump height and gravity we deduce the upwards speed 
     // for the character to reach at the apex.
     return Mathf.Sqrt(1 * targetJumpHeight * CharacterMotorMoving.gravity);
 }
 

}

IF you can't figure that out then check out the game to see WHAT the problem is with the sliding off of blocks, Idk if this is allowed but.. www.deltabug.bugs3.com