"Older Posts" suddenly stopped working

I have a site built using a child theme based on Word Press’s twenty eleven theme. Today, for no determinable reason the “Older Posts” button stopped functioning properly. When clicked, it goes to goes to /page/2 but shows the same posts as the home page. The site has worked correctly for years and I haven’t made any changes. What happened? Thanks.

Here’s my main loop if this helps. Aside from removing 2 categories from it, it’s what came with the twenty eleven theme.

‘<?php
if ( is_home() ) {
query_posts( ‘cat=-22,-47’ );
}
if ( have_posts() ) :
twentyeleven_content_nav( ‘nav-above’ ); ?>
while ( have_posts() ) : the_post();
get_template_part( ‘content’, get_post_format() );
endwhile;
twentyeleven_content_nav( ‘nav-below’ );
else : ?>
<article id=”post-0″ class=”post no-results not-found”>
<header class=”entry-header”>
<h1 class=”entry-title”>
<?php _e( ‘Nothing Found’, ‘twentyeleven’ ); ?></h1>
</header><!– .entry-header –>
<div class=”entry-content”>
<p><?php _e( ‘Apologies, but no results were found for the requested archive. Perhaps searching will help find a related post.’, ‘twentyeleven’ ); ?></p>
get_search_form();
</div><!– .entry-content –>
</article><!– #post-0 –>

<?php endif; ?>’