Dear Klemen! Problem: When you press the button, the command is not played

Klemen if u hear :((( help please
When you click a button in your GUI on your own server with the mod installed, the command from the plugin is not played.
Button who should execute plugin command on server

The procedure that was supposed to execute the plugin command on the server

In the project settings, I set it to a server mod, I installed my mod on the server and installed it in the game client, I go to the GUI, click on this button, the interface closes, and the command doesn't play.
The plugin is called Advanced Seasons, and I want the /calendar command to be executed when the interface is closed.