Hello,
It's possible the plugin you are using is attempting to use a PHP 5.4 path for the internal cPanel PHP (which causes their autoload script to not load/function). Now that cPanel uses an internal PHP 5.6 version, the plugin may have stopped working. You can review the output from /usr/local/cpanel/logs/error_log when reproducing this error in the cPanel UI if you want to see the full error output.
I recommend reporting this issue to the support team for the plugin you are using so they can take a closer look and publish a resolution if necessary.
Thank you.
