SmartCrawl Pro: causing the site not to work properly.

The SmartCrawl Pro plugin is causing a problem in all of my WP website that has Divi installed. I receive the fatal error like:

Fatal error: ob_start(): Cannot use output buffering in output buffering display handlers in /home/******/public_html/********/wp-content/plugins/modern-events-calendar/app/libraries/skins.php on line 253

Please help.