Raycasts in Multiplayer Network

I recently started a FPS Project and I watched some tutorials on YouTube. Because everything worked perfect, I had the idea, to make it Multiplayer playable.

So here is my code: (Some variables have German names because I am from Germany)

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.Networking;
 using UnityEngine.UI;
 
 public class Waffenscript : NetworkBehaviour
 {
 
     public bool automatisch;
     [SyncVar] public int gunDamage;
 
     public int ammoCapacity;
     public int ammo;
     public float reloadTime;
     public float fireRate;
     public float weaponRange;
     public float hitForce;
     public Transform shotSpawn;
     public GameObject shotSound;
     public GameObject reloadSound;
     public GameObject bluteffekt;
     [SyncVar] Vector3 rayOrigin = new Vector3();
     Text ammotext;
     Text reloadtext;
     Text distanztext;
 
     private Camera kamera;
     private WaitForSeconds shotDuration = new WaitForSeconds(.05f);
     private float nächsterSchuss;
     private LineRenderer schussLinie;
     private bool reloading;
     private float zwischenzeit;
     RaycastHit hit;
 
     void Start()
     {
         ammotext = GameObject.Find("/Canvas/Ammo/").GetComponent<Text>();
         reloadtext = GameObject.Find("/Canvas/Reload/").GetComponent<Text>();
         distanztext = GameObject.Find("/Canvas/Distanz/").GetComponent<Text>();
         reloading = false;
         reloadtext.text = ("");
         ammotext.text = ammo.ToString();
         ammo = ammoCapacity;
         schussLinie = GetComponent<LineRenderer>();
         kamera = GetComponentInParent<Camera>();
     }
 
     void Update()
     {
 
         if (reloading)
         {
             reloadtext.text = (reloadTime + zwischenzeit - Time.time).ToString("F2");
         }
 
         if (reloadTime + zwischenzeit - Time.time < 0)
         {
             reloadtext.text = "";
         }
 
         if (Input.GetButtonDown("Reload"))
         {
             StartCoroutine(Reload());
             Instantiate(reloadSound, transform.position, transform.rotation);
         }
 
           if (Input.GetButtonDown("Fire1") && Time.time > nächsterSchuss && (ammo > 0) && !reloading && !automatisch)
           {
              ShootNotAuto();  
           }
 
         if (Input.GetButton("Fire1") && Time.time > nächsterSchuss && (ammo > 0) && !reloading && automatisch)
         {
             ShootAuto();
         }
 
     }
         
     
 
     private void FixedUpdate()
     {
         RaycastHit distanz;
         schussLinie.SetPosition(0, shotSpawn.position);
         Vector3 rayOrigin = kamera.ViewportToWorldPoint(new Vector3(0.5f, 0.5f, 0.0f));
         Debug.DrawRay(rayOrigin, kamera.transform.forward * weaponRange, Color.green);
         Physics.Raycast(rayOrigin, kamera.transform.forward, out distanz);
         distanztext.text = (distanz.distance.ToString("F2") + " m");
     }
 
     [Client]
     void ShootNotAuto()
     {
         nächsterSchuss = Time.time + fireRate;
 
         StartCoroutine(SchussEffekt());
         Instantiate(shotSound, transform.position, transform.rotation);
 
         rayOrigin = kamera.ViewportToWorldPoint(new Vector3(0.5f, 0.5f, 0.0f));
 
         schussLinie.SetPosition(0, shotSpawn.position);
 
         if (Physics.Raycast(rayOrigin, kamera.transform.forward, out hit, weaponRange))
         {
             schussLinie.SetPosition(1, hit.point);
             if (hit.transform.gameObject.tag == "Gegenstand_Bewegbar")
             {
                 hit.rigidbody.AddForce(-hit.normal * hitForce);
             }
 
             if (hit.transform.gameObject.tag == "Spieler")
             {
                 CmdDamager(hit.transform.gameObject);
             }
         }
         else
         {
             schussLinie.SetPosition(1, rayOrigin + (kamera.transform.forward * weaponRange));
         }
 
         ammo = ammo - 1;
         ammotext.text = ammo.ToString();
     }
 
     [Client]
     void ShootAuto()
     {
         nächsterSchuss = Time.time + fireRate;
 
         StartCoroutine(SchussEffekt());
         Instantiate(shotSound, transform.position, transform.rotation);
 
         rayOrigin = kamera.ViewportToWorldPoint(new Vector3(0.5f, 0.5f, 0.0f));
         RaycastHit hit;
 
         schussLinie.SetPosition(0, shotSpawn.position);
 
 
         if (Physics.Raycast(rayOrigin, kamera.transform.forward, out hit, weaponRange))
         {
             schussLinie.SetPosition(1, hit.point);
             if (hit.transform.gameObject.tag == "Gegenstand_Bewegbar")
             {
                 hit.rigidbody.AddForce(-hit.normal * hitForce);
             }
 
             if (hit.transform.gameObject.tag == "Spieler")
             {
                 Instantiate(bluteffekt, hit.point, transform.rotation);
                 CmdDamager(hit.transform.gameObject);
             }
 
         }
         else
         {
             schussLinie.SetPosition(1, rayOrigin + (kamera.transform.forward * weaponRange));
         }
 
         ammo = ammo - 1;
         ammotext.text = ammo.ToString();
     }
 
     [Command]
     void CmdDamager(GameObject ziel)
     {
         ziel.GetComponent<HealthManager>().RpcSchaden(gunDamage);
     }
 
     private IEnumerator SchussEffekt()
     {
         schussLinie.enabled = true;
         yield return shotDuration;
         schussLinie.enabled = false;
     }
 
 
     private IEnumerator Reload()
     {
         zwischenzeit = Time.time;
         reloading = true;
         yield return new WaitForSeconds(reloadTime);
         ammo = ammoCapacity;
         ammotext.text = ammo.ToString();
         reloading = false;
     }
 }

This script is on the gun the Player holds in his hand. When it detects the tagged "Player" it should do this:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine.Networking;
 using UnityEngine;
 
 public class HealthManager : NetworkBehaviour {
 
     public int maxHealth = 100;
     [SyncVar] public int health = 100;
 
     void Awake () {
         health = maxHealth;
     }
 
     [ClientRpc]
     public void RpcSchaden(int damage)
     {
         health = health - damage;
 
         Debug.Log(transform.name + " hat noch " + health + "Leben.");
 
         if (health <= 0)
         {
             Die();
         }
     }
 
     [Client]
     void Die()
     {
         transform.position = Vector3.zero;
     }
 
 }
 

I don't know why it won't work and I am actually very confused because of all the things that needed to be changed. It would be nice if somebody could help me.