For another good samaritan fighting with this problem and with its own anxiety, like me:
Same case than other problems while building and setting up your website: its a matter of time!
mydomain(dot)com(dot)ar started to work instantly.
www(dot)mydomain(dot)com(dot)ar took a few (15) minutes.
When you see that something is working, and something is not, you start to think “hey, this should be working too”.