[Bikken]

Replace SendPlayerMessage with SendClientMessage

Edit - forgot, so the new code comes like this under SendClientMessage

pawn Код:

public OnPlayerConnect(playerid)
{
    SendClientMessage(playerid, COLOR_GREEN, "Welcome to our server plz type /register or /login.");
    return 1;
}

Also, after #define a_samp, do #define COLOR_GREEN a space after.

SendPlayerMessage is now SendClientMessage, so the code above sends a text to every player on connection, the text provided in a green colour. Hope this helps. Also, look on Color embedding, if you want to add multiple colours.