[Shadow0707]

PHP Code:

#define COLOR_BLACK 0x000000AA
new slex_part1_zone;
public OnPlayerConnect(playerid)
{
    SetGameModeText("SLEX 4.0");
    slex_part1_zone = CreatePlayerGangZone(playerid, 2903.1584, -768.6727, 3000.0000, -800.2560);
    
    return 1;
}
public OnPlayerSpawn(playerid)
{
    PlayerGangZoneShow(playerid, slex_part1_zone, COLOR_BLACK);
    return 1;
} 


this should do it.

EDIT: I tried your coordinates and it shows this.

PHP Code:

CreatePlayerGangZone: MaxX, MaxY must be bigger than MinX, MinY. Not inversely!
CreatePlayerGangZone: 2903.158447, -768.672729, 3000.000000, -800.255981 


The error is understandable and can be easily fixed.