By stop working do you mean the guns just don't shoot? Do they still aim at things? Vehicles have a max weight limits and if they are over that weight then they will overheat and be unable to fire. If you have the HUD wired up then you should be able to see if there is a red bar filled up next to the radar readout to determine if it is overheated.

You don't have to link the ammo to the reactor, you just would need to link the guns to the reactor. Ammo is detected automatically on the contraption by the reactor as long as it is properly parented to a gate that is then parented to a physical part of the mech such as a hip or torso.

My robot weighs 42255 kg. On the server, as far as I know, there is no weight limit. In addition, I can shoot with laser weapons. This robot has 2 powerful laser guns, and 2 small laser guns.
And i see, he dont overheat

In addition, even if I do not install ballistic weapons on the robot, it still will not shoot.
Maybe this is a conflict with other add-ons? Can an ACF or some other add-on interfere with Dak Tek?

There shouldn't be any conflicts with DakTek and ACF, I've tested that before. Nothing should really be causing an issue with something like that.

I see that the problem is not heat related, but I am now confused as you have stated "even if I do not install ballistic weapons on the robot it still will not shoot" but if there are no ballistics on the robot then what are you trying to shoot? Missiles? Lasers? ACF weapons?

I might need to take a look at it on my server to see if I can see the issue, but here's some things I'd check:

-Is the gate parented to the base props properly? Oftentimes the default setting for gates is to be welded to them.
-Is the ammo the right kind for the gun you have? Possibly you could be using IS ammo for a Clan weapon or Clan ammo for an IS weapon or maybe the ammo spawned incorrectly and needs to be updated manually.
-Were the guns linked up to the reactor? I'd assume you do that properly since you set up lasers right, but it is always good to recheck the basics.
-Are the guns, ammo, and reactor all part of the same contraption? If you check total mass of the vehicle from each of those parts it should return the same number.

Maybe I will connect to your server, and we will try to solve this problem?
I would be glad to see ballistic weapons and rockets on my mech.

Alright, server address is 73.216.100.235:27015. Password is daktek.

Ohhh.. Maybe I connected something wrong on mech, but separately it worked, thanks for some tips.
But as before, if I’m the parent gun and cosmetic props on the arm (I use the gun model instead of the arm, as shown in the tutorial) and attach the gun model to Torso using adv Ballsocket, all guns on mech stop working, even those that before creating advBallsocket worked.
There are no problems with overheating

The only way I can think of that could cause all the guns to stop working from the addition of a new gun would be an overloaded reactor or some sort of bug in the code. Would definitely need to see it if that is the case.

What size of reactor are you using and how heavy is the mech before you add the guns and how heavy is it after you add the guns?