Chrome extension inline install stopped working

[Sergej Vukovic]

We had chrome inline installation on our website for couple of weeks , and yesterday it stopped working for no reason . Nothing has been changed . We set

<link rel="chrome-webstore-item" href="https://chrome.google.com/webstore/detail/nbnfjhcjapmimpgljikhfhgjlpdldpaf">

and

created a simple button to trigger install

<a onclick="chrome.webstore.install()" href="javascript:void(0);">
<button class="cta-button">Install chrome extension</button>
</a>

Site is verified in webmaster tools as suggested by the guide and is visible on chrome web store.

[Eric Lawrence]

What's the URL of the site, and what exactly happens when the user clicks the button?