Uncaught Exception Warning From WordPress Core

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Error Details
=============
An error of type E_ERROR was caused in line 404 of the file /public_html/wp-content/plugins/uptime-robot-monitor/functions.php. Error message: Uncaught Exception: DateTime::__construct(): Failed to parse time string (@) at position 0 (@): Unexpected character in /public_html/wp-content/plugins/uptime-robot-monitor/functions.php:404
Stack trace:
#0 /public_html/wp-content/plugins/uptime-robot-monitor/functions.php(404): DateTime->__construct(‘@’)
#1 /public_html/wp-content/plugins/uptime-robot-monitor/admin-dashboard.php(38): urpro_sectotime(NULL, ‘short’)
#2 /public_html/wp-admin/includes/template.php(1304): urpro_admin_dashboard(”, Array)
#3 /public_html/wp-admin/includes/dashboard.php(241): do_meta_boxes(Object(WP_Screen), ‘column4’, ”)
#4 /public_html/wp-admin/index.php(148): wp_dashboard()
#5 {main}
thrown