gms_script_set_logout - GameMaker Server

//Step Event of Ally
if !gms_instance_is_owner(id)
{
gms_script_set_logout(scr_logout);
}
//scr_logout script
if !player_id_exists(gms_instance_get_owner(id))
{
    instance_destroy();
}
//player_id_exists script (Your script. :P)
for(n = 0; n < gms_other_count(); n += 1;)
{
    if gms_other_find(n) == argument0
        return true;
}
return false;

But it is not working, I know I am doing everything wrong. xD
Please tell me what am I doing wrong? (Actually, I am doing everything wrong. lol)
Thanks! :)

Just leave what you had in the step event of the Ally object. Add the call to gms_script_set_logout to a game start event somewhere so it's executed when your game starts.

Try this in the logout script:
[gml]
with Ally
{
if gms_instance_get_owner(id) == argument0.player_id
{
instance_destroy()
}
}
[/gml]

Now I changed code to this:

//Step
if !gms_instance_is_owner(id)
{
if !player_id_exists(gms_instance_get_owner(id))
{
instance_destroy();
}
}
//Logout script
with(obj_ally)
{
if gms_instance_get_owner(id) == argument0.player_id
{
instance_destroy();
}
}
//obj_control's game start
gms_script_set_logout(scr_logout);

But not working, is it because gms_settings is being called on create event of obj_control? because Game Start and Create event are very likely executes at once.
Possibly it is like update checking? (like update checking code should be executed some time after gms_settings.)

It doesn't matter when you execute gms_script_set_logout, as long as it's after gms_init (GM:Studio). Does the ally at least get destroyed when the other player logs out? That's what the code should do.

It not destroys and starts following player.

Would you be able to mail me your gmk/gmz at gamemakerserver@outlook.com, so that I can take a look?