amit_kosti

function cust_field_text($column_name){
        if($column_name === 'cust_col'){
                 the_meta();
          }
}
add_action('manage_posts_custom_column', 'cust_field_text', 10, 2);
function cust_fields($defaults){
    $defaults['cust_col'] = __('cust fields');
    return $defaults;
}

add_filter('manage_posts_columns', 'cust_fields');

Somehow I managed to show all used custom field with values in post-list.
Used above code in functions.php

here is image – https://imgur.com/6HLMW

Try Re-saving you permalink structure. That worked fine for me.

Thanks ipstenu,
RESET of Permalinks worked for me.