The screenshots you included show no indication of any errors. You have CentOS 7 which no longer uses chkconfig and service commands: they have both been replaced by the systemd command
systemctl but there are backwards compatibility scripts in place that convert chkconfig and service into systemctl commands for you: hence the "Forwarding request to..." lines you see. These are not errors, they are information - you are expected to look at those and see the relevant systemctl commands you should use instead of the chkconfig/service ones you issued and use those in future.
When you start the service, how are you determining that it is not starting? I see no
systemctl status httpd.service commands for example.
When I contacted my host provider, they told me that #selinux was enabled on my server but they have disabled it now.
Time to find a smarter hoster then. You should _never_ disable selinux. Now you'll have to turn it back on again. To do that, first check in /etc/sysconfig/selinux and see if they did disable it or just set it to permissive. If it says disabled then change that to permissive first, then
touch /.autorelabel && reboot and wait while it relabels the filesystem and once your server comes back up again (which may take a little longer than usual because of the relabel), then edit the /etc/sysconfig/selinux file again and change permissive to enabled and
touch /.autorelabel && reboot again. Then tell your hoster to never disable selinux again.
As to the problem of httpd not starting: are you sure it's not running but inaccessible due to the firewall? On CentOS 7, it uses firewalld by default and you manipulate its firewall rules using the
firewall-cmd command. For example,
firewall-cmd --enable-service=httpd would allow http requests through. That needs to be run again with the --permanent switch to make the change persistent over a reboot.
