Reoccurring error

Hey,

I love the plugin you have made. It is exactly what I’ve been looking for.

However, there is a slight issue, every now and then I get the following error message appear at the top of the site:

Warning: file_get_contents(): php_network_getaddresses: getaddrinfo failed: No address associated with hostname in /home/yourdoma/public_html/wp/wp-content/plugins/custom-nextpage/custom-nextpage.php on line 42

Warning: file_get_contents(http://thirdactfilm.com/wp-content/plugins/custom-nextpage/css/custom-nextpage-style.css): failed to open stream: php_network_getaddresses: getaddrinfo failed: No address associated with hostname in /home/yourdoma/public_html/wp/wp-content/plugins/custom-nextpage/custom-nextpage.php on line 42

What would be the best course of action to prevent this from happening again?

My website is: http://www.thirdactfilm.com

https://wordpress.org/plugins/custom-nextpage/