Unable to switch from LiteSpeed to Apache on Plesk server: Apache is not up within 30 secs

Connect to the server via SSH.

Create the file /usr/lib/systemd/system/httpd.service with the following content:

# cat /usr/lib/systemd/system/httpd.service
[Unit]
Description=The Apache HTTP Server
After=network.target remote-fs.target nss-lookup.target
Documentation=man:httpd(8)
Documentation=man:apachectl(8)

[Service]
Type=notify
EnvironmentFile=/etc/sysconfig/httpd
ExecStart=/usr/sbin/httpd $OPTIONS -DFOREGROUND
ExecReload=/usr/sbin/httpd $OPTIONS -k graceful
ExecStop=/bin/kill -WINCH ${MAINPID}
# We want systemd to give httpd some time to finish gracefully, but still want
# it to kill httpd after TimeoutStopSec if something went wrong during the
# graceful stop. Normally, Systemd sends SIGTERM signal right after the
# ExecStop, which would kill httpd. We are sending useless SIGCONT here to give
# httpd time to finish.
KillSignal=SIGCONT
PrivateTmp=true

[Install]
WantedBy=multi-user.target

Unmask the httpd service:

# systemctl unmask httpd

Re-enable it so the required symlinks are created automatically:

# systemctl disable httpd
# systemctl enable httpd

Start Apache:

# systemctl start httpd

Connect to the server via SSH.

Create the file /lib/systemd/system/apache2.service with the following content:

# cat /lib/systemd/system/apache2.service
[Unit]
Description=The Apache HTTP Server
After=network.target remote-fs.target nss-lookup.target

[Service]
Type=forking
Environment=APACHE_STARTED_BY_SYSTEMD=true
ExecStart=/usr/sbin/apachectl start
ExecStop=/usr/sbin/apachectl stop
ExecReload=/usr/sbin/apachectl graceful
PrivateTmp=true
Restart=on-abort

[Install]
WantedBy=multi-user.target

Unmask the apache2 service:

# systemctl unmask apache2

Re-enabled it so the required symlinks are created automatically:

# systemctl disable apache2
# systemctl enable apache2

Start Apache:

# systemctl start apache2