I've tried to run apache server with

sudo apachectl start
sudo apachectl stop

and I encountered these errors

AH00558: httpd: Could not reliably determine the server's fully qualified domain name, using exampleui-MacBookPro.local. Set the 'ServerName' directive globally to suppress this message (48)Address already in use: AH00072: make_sock: could not bind to address [::]:8080
(48)Address already in use: AH00072: make_sock: could not bind to address 0.0.0.0:8080
no listening sockets available, shutting down

AH00015: Unable to open logs
AH00558: httpd: Could not reliably determine the server's fully qualified domain name, using Hoonui-MacBookPro.local. Set the 'ServerName' directive globally to suppress this message
httpd (pid 6276?) not running

So I searched stackoverflow and exchanged ServerName localhost in etc/apache2/httpd.conf file to ServerName localhost:8080 and it was uncommented already.

It didn't change even after changing ServerName into

localhost
localhost:80
localhost:8080
127.0.0.1

and I also tried to kill process with kill -9 pid but nothing changed