Nagios check_http returning Cannot make SSL connection error on CentOS 7

I'm running a site on Apache (httpd) on a CentOS 7 host and monitoring it using Nagios on another CentOS 7 host. The configuration in Nagios is: define service { check_command check_http_url!/my_class/product/session!-f follow -S host_name mysite.com use critical-service service_description My Site Production servicegroups production-sites } This has been working until recently. Nagios is now reporting the following error: CRITICAL - Cannot make SSL connection. I have run the following and also see the error: [root@mynagiosserver-01 ~]# /usr/lib64/nagios/plugins/check_http -H mysite.com -u /my_class/product/session -f follow -S -v CRITICAL - Cannot make SSL connection. SSL initialized On the Nagios host, mysite.com maps to the Apache host IP address in the /etc/hosts file. Any ideas on how I can troubleshoot this further?