Trying to output content from page, works locally but not online

have you tried get_page() ?

$page_id = 123; // 123 should be replaced with a specific Page's id from your site,

$page = get_page( $page_id ); // You must pass in a variable to the get_page function. 

echo '<h3>'. $page->post_title .'</h3>';// echo the page title

echo apply_filters('the_content', $page->post_content); // Get Content and retain WordPress filters such as paragraph tags. 

http://codex.wordpress.org/Function_Reference/get_page

don’t forget to make sure you change the $page_id to match your live version