rigidbody player jump automatically.

I code one cube in rigidbody to move with rotate but when the "x face" of cube contact with ground the cube is jump automatically.

my code is :

     void FixedUpdate() {
         float mv =  rotationSpeed * Time.fixedDeltaTime * Input.GetAxis("Horizontal");
         
         //Debug.Log(mv);
         
            
            rigidbody.AddRelativeTorque( new Vector3(forceAmount * Input.GetAxis("Vertical"), 0.0f, 0.0f));
            //rigidbody.AddRelativeTorque( new Vector3(forceAmount * Input.GetAxis("Horizontal"), 0.0f, 0.0f));
         
         float rottatedGer = transform.eulerAngles.z ;
         // go to front or back
         // if greater than 270 go back else go front
         if ((rottatedGer < 269) && (rottatedGer > 91) ){
             Debug.Log(rottatedGer);
             if (rottatedGer < 271){
              transform.Rotate(0.0f,0.0f, rottatedGer -90);        
             }else if(rottatedGer >89){
                 transform.Rotate(0.0f,0.0f,rottatedGer +90);
             }
             
         }else{
             transform.Rotate(0.0f,0.0f,mv*-1);
         }
         
         transform.Translate(new Vector3( mv  * 3 *  Time.deltaTime,0.0f, 0.0f));
     }
      

Now how I can fix it that don't jump when I try to go to right.