NotServerException: ConnectedClients should only be accessed on server. error

Question

iam testing with multiplayer and get this error

NotServerException: ConnectedClients should only be accessed on server. Unity.Netcode.NetworkManager.get_ConnectedClients () (at Library/PackageCache/[email protected]/Runtime/Core/NetworkManager.cs:269) TeamPicker.SelectTeam (System.Int32 teamIndex) (at Assets/Assets/Scripts/TeamPicker.cs:12) UnityEngine.Events.InvokableCall1[T1].Invoke (T1 args0) (at <ab7de6937a4448b0a6ccd59e9820599a>:0) UnityEngine.Events.CachedInvokableCall1[T].Invoke (System.Object[] args) (at :0) UnityEngine.Events.UnityEvent1[T0].Invoke (T0 arg0) (at <ab7de6937a4448b0a6ccd59e9820599a>:0) UnityEngine.EventSystems.EventTrigger.Execute (UnityEngine.EventSystems.EventTriggerType id, UnityEngine.EventSystems.BaseEventData eventData) (at Library/PackageCache/[email protected]/Runtime/EventSystem/EventTrigger.cs:220) UnityEngine.EventSystems.EventTrigger.OnPointerClick (UnityEngine.EventSystems.PointerEventData eventData) (at Library/PackageCache/[email protected]/Runtime/EventSystem/EventTrigger.cs:277) UnityEngine.EventSystems.ExecuteEvents.Execute (UnityEngine.EventSystems.IPointerClickHandler handler, UnityEngine.EventSystems.BaseEventData eventData) (at Library/PackageCache/[email protected]/Runtime/EventSystem/ExecuteEvents.cs:57) UnityEngine.EventSystems.ExecuteEvents.Execute[T] (UnityEngine.GameObject target, UnityEngine.EventSystems.BaseEventData eventData, UnityEngine.EventSystems.ExecuteEvents+EventFunction1[T1] functor) (at Library/PackageCache/[email protected]/Runtime/EventSystem/ExecuteEvents.cs:272) UnityEngine.EventSystems.EventSystem:Update() (at Library/PackageCache/[email protected]/Runtime/EventSystem/EventSystem.cs:501)

the code is

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using Unity.Netcode;

public class TeamPicker : MonoBehaviour
{
    public void SelectTeam(int teamIndex)
    {
        ulong localClientId = NetworkManager.Singleton.LocalClientId;

        if(!NetworkManager.Singleton.ConnectedClients.TryGetValue(localClientId, out NetworkClient networkClient))
        {
            //throw new NotServerException("Only the server can find player objects from other clients.");
            return;
        }

        if(!networkClient.PlayerObject.TryGetComponent<TeamPlayer>(out TeamPlayer teamPlayer))
        {
            return;
        }

        teamPlayer.SetTeamServerRpc((byte)teamIndex);
    }
}

and

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using Unity.Netcode;

public class TeamPlayer : NetworkBehaviour
{
    [SerializeField] private Renderer teamColorRenderer;
    [SerializeField] private Color[] teamColors;

    private NetworkVariable<byte> teamIndex = new NetworkVariable<byte>(0);
     
    [ServerRpc]
    public void SetTeamServerRpc(byte newTeamIndex)
    {
        if(newTeamIndex > 3 ){ return; }

        teamIndex.Value = newTeamIndex;
    }

    private void OnEnable()
    {
        teamIndex.OnValueChanged += OnTeamChanged;
    }

    private void OnDisable()
    {
        teamIndex.OnValueChanged -= OnTeamChanged;
    }

    private void OnTeamChanged(byte oldTeamIndex, byte NewTeamIndex)
    {
        if (!IsClient) { return; }

        teamColorRenderer.material.SetColor("_BaseColor", teamColors[NewTeamIndex]);
        Debug.Log("Clicked");
        Debug.Log(teamColors[NewTeamIndex]);
    }
}