Error Publishing A a new Post ( Blog )

Hi I am getting this error from your plugin when I try to publish a post.

Fatal error: Uncaught Error: Class 'Google_Service_Calendar' not found in /home/customer/www/productsbywomen.com/public_html/wp-content/plugins/simple-calendar-google-calendar-pro/includes/feeds/google-pro.php:174 Stack trace: #0 /home/customer/www/productsbywomen.com/public_html/wp-content/plugins/simple-calendar-google-calendar-pro/includes/feeds/google-pro.php(99): SimpleCalendar\Feeds\Google_Pro->set_client() #1 /home/customer/www/productsbywomen.com/public_html/wp-content/plugins/google-calendar-events/includes/objects.php(286): SimpleCalendar\Feeds\Google_Pro->__construct('') #2 /home/customer/www/productsbywomen.com/public_html/wp-content/plugins/google-calendar-events/includes/objects.php(191): SimpleCalendar\Objects->get_object('google-pro', 'feed', '') #3 /home/customer/www/productsbywomen.com/public_html/wp-content/plugins/google-calendar-events/includes/functions/shared.php(87): SimpleCalendar\Objects->get_feed('google-pro') #4 /home/customer/www/productsbywomen.com/public_html/wp-content/plugins/google-calend in /home/customer/www/productsbywomen.com/public_html/wp-content/plugins/simple-calendar-google-calendar-pro/includes/feeds/google-pro.php on line 174

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