Error

Hello, the plugin is giving an error a few times. And in this error the site goes offline for a few seconds / minutes.
Follows the error report

An error of type E_ERROR was caused at line 145 of file /var/www/html/wp-content/plugins/referralcandy-for-woocommerce/includes/class-rc-order.php. Error Message: Uncaught Error: Cannot use object of type WP_Error as array in /var/www/html/wp-content/plugins/referralcandy-for-woocommerce/includes/class-rc-order.php:145
Stack trace:
#0 /var/www/html/wp-content/plugins/referralcandy-for-woocommerce/includes/class-wc-referralcandy-integration.php(133): RC_Order->submit_purchase()
#1 /var/www/html/wp-includes/class-wp-hook.php(288): WC_Referralcandy_Integration->rc_submit_purchase(2459)
#2 /var/www/html/wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters(NULL, Array)
#3 /var/www/html/wp-includes/plugin.php(465): WP_Hook->do_action(Array)
#4 /var/www/html/wp-content/plugins/woocommerce/includes/class-wc-order.php(360): do_action(‘woocommerce_ord…’, 2459, Object(WC_Order))
#5 /var/www/html/wp-content/plugins/woocommerce/includes/class-wc-order.php(230): WC_Order->status_transition()
#6 /var/www/html/wp-content/plugins/woocommerce/includes/admin/meta-boxes/class-wc-meta-box-order-data.php(620): WC_Order->save()
#7 /var/www/html/wp-includes/class-wp-hook.php(286): WC_

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