cPanel free SSL issue

This means server is currently running EasyApache 3, our older Apache and PHP management/configuration system. EasyApache 3 is scheduled for deprecation and will reach its End-of-Life on December 31, 2018. At that time, maintenance and security fixes will no longer be released for this software. As outlined in this blog post, cPanel/WHM updates will also not be possible after WHM 76.

You need upgrade the server to EasyApache 4