Why is apache2 not working?

Question

Apache HTTP Server

Why doesn’t it work, it seems to be running, I check the status like this:
sudo service apache2 status
As I understand it, does it work?

Change the port here:

nano /etc/apache2/ports.conf
nano /etc/apache2/sites-enabled/000-default.conf

I put 8081, because 80 is busy.
I ping my IP - it does not work, I tried to specify IP: 8081 - the same thing.