warning messages on site

I am getting these warnings at the top of the page
Warning: file_get_contents(/home/lovewxnw/public_html/wp-content/plugins/whmcs-wordpress-integration/cache/ab3fcf0ab7e900478359b9708255c62c.txt): failed to open stream: No such file or directory in /home/lovewxnw/public_html/wp-content/plugins/whmcs-wordpress-integration/includes/class-whmcs-wordpress-integration.php on line 376

Warning: file_get_contents(/home/lovewxnw/public_html/wp-content/plugins/whmcs-wordpress-integration/cache/ab3fcf0ab7e900478359b9708255c62c.txt): failed to open stream: No such file or directory in /home/lovewxnw/public_html/wp-content/plugins/whmcs-wordpress-integration/includes/class-whmcs-wordpress-integration.php on line 376

Warning: file_get_contents(/home/lovewxnw/public_html/wp-content/plugins/whmcs-wordpress-integration/cache/ab3fcf0ab7e900478359b9708255c62c.txt): failed to open stream: No such file or directory in /home/lovewxnw/public_html/wp-content/plugins/whmcs-wordpress-integration/includes/class-whmcs-wordpress-integration.php on line 376