Can't run the Newsletter cron from the crontab. Here are the PHP errors resulting in a 500 Internal Server Error.
[10-Feb-2017 15:40:01 America/Los_Angeles] PHP Warning: include_once(/includes/sp-load.php): failed to open stream: No such file or directory in /home/surfseo/public_html/plugins/newsletter/newslettercron.php on line 8
[10-Feb-2017 15:40:01 America/Los_Angeles] PHP Warning: include_once(): Failed opening '/includes/sp-load.php' for inclusion (include_path='.:/usr/lib/php:/usr/local/lib/php') in /home/surfseo/public_html/plugins/newsletter/newslettercron.php on line 8
[10-Feb-2017 15:40:01 America/Los_Angeles] PHP Warning: include_once(SP_CTRLPATH/seoplugins.ctrl.php): failed to open stream: No such file or directory in /home/surfseo/public_html/plugins/newsletter/newslettercron.php on line 9
[10-Feb-2017 15:40:01 America/Los_Angeles] PHP Warning: include_once(): Failed opening 'SP_CTRLPATH/seoplugins.ctrl.php' for inclusion (include_path='.:/usr/lib/php:/usr/local/lib/php') in /home/surfseo/public_html/plugins/newsletter/newslettercron.php on line 9
[10-Feb-2017 15:40:01 America/Los_Angeles] PHP Fatal error: Class 'SeoPluginsController' not found in /home/surfseo/public_html/plugins/newsletter/newslettercron.php on line 10