Google-fu is drawing a blank because this question is so specific. So here I am.
Basically I have a router machine running Kali (don't ask, no I can't change it) that works fine so long as it's logged in. And when it's not logged in, it still works fine- for 15 minutes before the machine suspends.
When I'm logged in, I have it configured so that it doesn't auto-suspend. It does auto-lock, but it doesn't auto-suspend, unless I haven't logged in yet. This is a good thing, and it means it works fine so long as i log in. But since this is acting as a router, I don't want to have to open a GUI on it any time it needs to restart, and I definitely don't want to have to wake the machine back up every time.
iptables and SSH work just fine when I'm not logged in and the PC is enabled. I can log in with SSH just fine, but logging in with SSH doesn't stop the loading.
Kali is installed with GNOME desktop environment.