[Threshold]

There is no 'playerid' parameter in SendClientMessageToAll

See Here:
https://sampwiki.blast.hk/wiki/SendClientMessageToAll

pawn Код:

stock ClearChatForAll(playerid)
{
    SendClientMessageToAll(-1,"SERVER: Admin have clear the chat box.");
    return 1;
}

stock ShowPlayerStats(playerid)
{
    SendClientMessageToAll(-1,"SERVER: Natan is work. keep it UP.");
    return 1;
}

NOTE: If ClearChatForAll is supposed to clear the chat as well, I recommend using:

pawn Код:

for(new i = 0; i < 100; i++)
{
    SendClientMessageToAll(-1, " ");
}