Cannon fires straight upward

I'm trying to simulate a cannon for my game.

It's given a target Vector, where the cannon ball should be fired at. I want a realistic calaculation of the trajectory path, the formula is included in the script.

At the moment, I have not found a solution for the occuring problem; the cannonball lifts straight up (90°) and falls down after a period of time (on the same spot = "Exit".position). The cannonball is a rigibody which is assigned to the cannon. Here's the script for the logic:

      protected override void Update()
         {
           if (Input.GetKeyDown("q"))
             {
                 if (canFire) FireCannon();
                 else canFire = true;
             }
     }
        private void FireCannon()
     {
 
         Vector3 pos = transform.FindChild("Exit").position;
         float dist = Vector3.Distance(pos, target);
                 
         float Vi = Mathf.Sqrt(dist * -Physics.gravity.y / (Mathf.Sin(Mathf.Deg2Rad * angle * 2)));
         float Vy, Vz; 
 
         Vy = Vi * Mathf.Sin(Mathf.Deg2Rad * angle);
         Vz = Vi * Mathf.Cos(Mathf.Deg2Rad * angle);
         
         Vector3 localVelocity = new Vector3(0f, Vy, Vz);
         Vector3 globalVelocity = transform.TransformVector(localVelocity);
         
         Rigidbody clone = Instantiate(projektil, pos, transform.rotation) as Rigidbody;
         clone.AddForce(globalVelocity * 1000);
         
         canFire = false;    
     }

I have worked quite long to find an error but this was without a result. I hope you can help me here.