can't click the close button

Not having any issues on my server, but it's probably a Layering issue. 

That is, some other plugin's transparent panel is on top of the Server Info panel and it is getting clicked vs. the button underneath.

Start looking at your other plugins on your server and perhaps move their panels or disable those plugins.  I've seen several plugins do this on my server and have to make those changes.

If you want to know more about layering, go to the very bottom of this link and read the Layer options section.

https://docs.oxidemod.com/guides/developers/basic-cui/basic-cui

Though this isn't the button in question, it is an example of that I'm talking about...

254     var helpButtonName = container.Add(helpChatButton, "Overlay");

Line 254 might need to be changed to Overall vs. Overlay.