I have produced a custom key in Wordpress known as classifieds and added a couple of posts.

I can tell the posts under /classifieds/publish-title

However, I'm attempting to retrieve all posts from /classifieds but I get a 404 error.

I have adopted instructions here:

http://codex.wordpress.org/Custom_Post_Types

and that i produced a classifieds-page.php using the following code provided for the reason that link:

$loop = new WP_Query( array( 'post_type' => 'classified', 'posts_per_page' => 10 ) );
while ( $loop->have_posts() ) : $loop->the_post();
the_title();
echo '<div class="entry-content">';
the_content();
echo '</div>';
endwhile;

However, basically write this:

$loop = new WP_Query( array( 'posts_per_page' => 10 ) );
while ( $loop->have_posts() ) : $loop->the_post();
the_title();
echo '<div class="entry-content">';
the_content();
echo '</div>';
endwhile;

it will shows the most recent 10 posts. I am certain since this should be something connected to the publish type itself.

To make certain, I've done the entire example much like in here:

http://codex.wordpress.org/Custom_Post_Types

the same names and i'm unable to result in the query, it shows no results.

I am really frustrated.

Are you able to publish where you apply the register_publish_type() function?

One common error would be to combine the plurality from the title. Check to make certain the very first parameter is 'classified' instead of 'classifieds'