This plugin is against Valves plugin policies. Adding this plugin to your server will get your server and steam account banned by Valve. You won't be able to host any CS:GO servers again if you get banned. Read https://dathost.net/blog/all-you-need-to-know-about-valves-plugin-policies/ for more info.

Valve recently made a change to how their CS:GO servers operate. To start your CS:GO server, you’ll now need a Gameserver Login Token (GSLT) to be registered with your server.

Step 1 - Go to the GSLT creation page

You can create a token for your game servers by going to Valve’s official steam gameserver login token page here:
http://steamcommunity.com/dev/managegameservers

Step 2 - Create your token

To create a token you’ll need to fill in the two fields at the bottom of the page under “Create a new game server account”:

App ID: Fill in the ID of the game you want to create a token for. In this case, 730 for CS:GO.
Memo: Fill in the name of your new token. Make sure it is something you remember so you know which server this is for. For example, it could be the same as the hostname of your server.

Step 3 - Get the ID of your newly generated token

Once you click create, your “Login Token” will appear. Simply copy the string and paste it in the input field below:

You can also update your token any time under "Edit".