My site is http://example.com/en/
I made a favicon for it.
In the head I have:
<link rel="shortcut icon" href="/favicon.ico" type="image/x-icon">
I can see the favicon.ico using the URL http://example.com/favicon.ico
But any browser doesn't show it. Help, please.
I see it used as icon when I browse to your page.
If you have visited your page before (duh!) it's likely because the browsers remember that there wasn't any icon there before, and don't update it right away. Browsers remember the icons for different sites, so that they don't have to request it every time that the site name is shown (for example in the bookmarks or the history).
Also, it's not guaranteed that every user sees the favicon, some browsers simply doesn't display some icons sometimes, for no apparent reason.