[SWAT4]

try this

pawn Код:

CMD:healall(playerid,params[])
{
    new string[200];
    LoginCheck(playerid);
    if(User[playerid][accountAdmin] >= 4)
    {
        foreach(Player, i)
        {
        PlayerPlaySound(i,1057,0.0,0.0,0.0);
        SetPlayerHealth(i,100.0);
        }
        }
        format(string, 128, "[HEAL] "white"Everyone has been healed by %s.", GetName(playerid));
        SendAMessage(COLOR_RED, string);
    }
    else return SendClientMessage(playerid, -1, "» "red"You are not authorized to use this command.");
}

Hope it works
im not rly sure i didn't test ,
i made some changes so Please Friendly Replys