[root@free-lancer ~]# service nginx restart
Redirecting to /bin/systemctl restart nginx.service
Job for nginx.service failed because the control process exited with error code. See "systemctl status nginx.service" and "journalctl -xe" for details.
[root@free-lancer ~]# cat /var/log/nginx/error.log
2021/07/05 19:11:23 [emerg] 1410#1410: bind() to 0.0.0.0:80 failed (98: Address already in use)
2021/07/05 19:11:23 [emerg] 1410#1410: bind() to [::]:80 failed (98: Address already in use)
2021/07/05 19:11:23 [emerg] 1410#1410: bind() to 0.0.0.0:80 failed (98: Address already in use)
2021/07/05 19:11:23 [emerg] 1410#1410: bind() to [::]:80 failed (98: Address already in use)
2021/07/05 19:11:23 [emerg] 1410#1410: bind() to 0.0.0.0:80 failed (98: Address already in use)
2021/07/05 19:11:23 [emerg] 1410#1410: bind() to [::]:80 failed (98: Address already in use)
2021/07/05 19:11:23 [emerg] 1410#1410: bind() to 0.0.0.0:80 failed (98: Address already in use)
2021/07/05 19:11:23 [emerg] 1410#1410: bind() to [::]:80 failed (98: Address already in use)
2021/07/05 19:11:23 [emerg] 1410#1410: bind() to 0.0.0.0:80 failed (98: Address already in use)
2021/07/05 19:11:23 [emerg] 1410#1410: bind() to [::]:80 failed (98: Address already in use)
2021/07/05 19:11:23 [emerg] 1410#1410: still could not bind()
2021/07/05 19:13:28 [emerg] 1443#1443: bind() to 0.0.0.0:80 failed (98: Address already in use)
2021/07/05 19:13:28 [emerg] 1443#1443: bind() to [::]:80 failed (98: Address already in use)
2021/07/05 19:13:28 [emerg] 1443#1443: bind() to 0.0.0.0:80 failed (98: Address already in use)
2021/07/05 19:13:28 [emerg] 1443#1443: bind() to [::]:80 failed (98: Address already in use)
2021/07/05 19:13:28 [emerg] 1443#1443: bind() to 0.0.0.0:80 failed (98: Address already in use)
2021/07/05 19:13:28 [emerg] 1443#1443: bind() to [::]:80 failed (98: Address already in use)
2021/07/05 19:13:28 [emerg] 1443#1443: bind() to 0.0.0.0:80 failed (98: Address already in use)
2021/07/05 19:13:28 [emerg] 1443#1443: bind() to [::]:80 failed (98: Address already in use)
2021/07/05 19:13:28 [emerg] 1443#1443: bind() to 0.0.0.0:80 failed (98: Address already in use)
2021/07/05 19:13:28 [emerg] 1443#1443: bind() to [::]:80 failed (98: Address already in use)
2021/07/05 19:13:28 [emerg] 1443#1443: still could not bind()
[root@free-lancer ~]# sudo netstat -plant | grep 80
tcp        0      0 0.0.0.0:80              0.0.0.0:*               LISTEN      1396/nginx: master
tcp6       0      0 :::80                   :::*                    LISTEN      1396/nginx: master
[root@free-lancer ~]#