/SLASHPLAY
How to stop a GMod server
Type quit in the server console to exit the server at once, disconnecting all players. Some hosting panels start it again by themselves.
quit
Exits the server process immediately, disconnecting all players.
quit Examples
quit Stop the server now.
On SLASHPLAY
Blocked on SLASHPLAY: use Restart or Stop on the server page.
What it does
On a hosted server the panel may start it again automatically depending on its restart setting.
The game's own description: Exit the engine.
Run it on your server
On a SLASHPLAY server, type it in the Console tab of the server page; the reply shows right under it. A value set there lasts until the server restarts. To keep it, add the line to garrysmod/cfg/server.cfg. New to this? Start a GMod server first.
Your own
GMod server.
From $0.03 an hour, only while it runs. New accounts get 6 free tokens.