how can I sync [SyncList] variable between client | Mirror Networking for Unity | Page 1

I have a struct like this

[System.Serializable]
public class PlayerInfo
{
    public int ConnId;
    public int TeamIndex;
    public int PlayerIndex;
}

[System.Serializable]
public class TeamInfo
{
    public int TeamIndex;
    public List<PlayerInfo> Player;

    public TeamInfo(int teamIndex, List<PlayerInfo> player = null)
    {
        TeamIndex = teamIndex;
        Player = new List<PlayerInfo>();
    }

    public TeamInfo() { }
}

//...
public readonly SyncList<TeamInfo> TheTeamInfo = new SyncList<TeamInfo>();

public override void  OnStartServer()
{
    base.OnStartServer();
    // init teaminfo, two teams
    for (int i = 0; i < 2; i++)
    {
        TheTeamInfo.Add(new TeamInfo(i));
    }
}

//...
[Command]
public void CmdAddPlayerToTeam(int teamIndex, int playerIndex, NetworkConnectionToClient conn = null)
{
    PlayerInfo newPlayer = new PlayerInfo
    {
        ConnId = conn.connectionId,
        TeamIndex = teamIndex,
        PlayerIndex = playerIndex
    };

    // to make Mirror detect the change and sync
    var teamRef = TheTeamInfo[teamIndex];
    teamRef.Player.Add(newPlayer);
    TheTeamInfo[teamIndex] = teamRef;
}

when I called the function CmdAddPlayerToTeam to change the TheTeamInfo, the client did not sync that, is me miss something? some one could help me?

#how can I sync [SyncList] variable between client