Starting nagios in linux cannot be solved through web Access

In linux, nagios cannot be started through web access. After nagios is configured in linux and started, you can enter http: // ipaddress/nagios through web. The page cannot be opened. online query is the reason for firewall, so I closed the firewall through service iptables stop and tried to open the page. However, after entering the page, I clicked hosts or services to report an internal apache error. Please contact the Administrator. This can only be further checked, it is best to check the reason why SELinux was started on the Internet. Close it and continue the test through getenforce setenforce 0, you can also modify selinux = "" in the/etc/SELINUX/config file to disabled, and then restart. If you do not want to restart the system, use the preceding command setenforce 0. Note: setenforce 1 sets SELinux to enforcing mode. setenforce 0 sets SELinux to permissive mode.