413 Request Entity Too Large errors occur when the request body is larger than the server is configured to allow. Here’s how you can fix it, depending on your web server:

• Apache: Set the LimitRequestBody directive in either your httpd.conf file or a local .htaccess file. (https://stackoverflow.com/a/3719358/1688568)
• Nginx: Set the client_max_body_size directive in nginx.conf (http://www.cyberciti.biz/faq/linux-unix-bsd-nginx-413-request-entity-too-large/)