[Konstantinos]

I understand the mistake. You have only one message on the MSGs and you are using random from MSGs while you have only one.

pawn Код:

new MSGs[1][256] = {
"» Bem vindo de volta", //320
// NOTE: Also if it's the last, it should have no ","
// ANOTHER NOTE: 128 is enough
};

pawn Код:

forward RandomMSGs();
public RandomMSGs()
{
    new string[256];
    new random1 = random(sizeof(MSGs));
    new random2 = random(sizeof(COLORS));
    format(string, sizeof(string), "%s", MSGs[random1]);
    SendClientMessageToAll(COLORS[random2],string);
    return 1;
}