[Mean]

You can use IsPlayerNPC.

Put some debug for NPCs in callbacks.

Here's a piece of code that will tell you the reason of the NPC disconnect:

pawn Код:

public OnPlayerDisconnect(playerid, reason) {
    if(IsPlayerNPC(playerid)) printf("NPC %i disconnected (reason: %i).", playerid, reason);
    // proceed with normal code
    return 1;
}

If the reason is kick/ban, check your "Kick" and "Ban(Ex)" codes.