I learned that Google needs some hours in order to track your website in Analytics.

Even if in the “Tracking Code” section it says “Tracking Code is not Working” reporting a check performed in a given minute, actually sometimes you just have to wait some hours to start “Receiving Data” without furthermore tinkering with your web code.

So just check the source code of your page, and if the Google Analytics snippet is included just give Google the time to update the tracking, without trusting too much the checking section.