Single post page: previous post link not working

Thank you, alchymyth.

I get a
Call to a member function get() on a non-object in /home4/bearstor/public_html/wp-includes/query.php on line 28

.. error with both suggestions, having taken out these lines:
$wp_query = null;
$wp_query = $original_query;

The call just doesn’t like the new parameter.

the error message was caused by my mistake, I suggested the wrong location to add the line to get the paged parameter.

this relevant code section seems to work:

<?php 

				$post_id=get_the_ID();

$tags = wp_get_post_tags($post_id);
foreach ( $tags as $tag ) {
	$tag_array[] = $tag->term_id;
}

$paged = get_query_var( 'paged' ) ? get_query_var( 'paged' ) : 1;

$original_query = $wp_query;
$wp_query = null;
$args=array('posts_per_page'=>3,
'tag__in' => $tag_array,
'post__not_in' => array($post_id),
'paged' => $paged
);
$wp_query = new WP_Query( $args );

you also need to add this to functions.php of your theme:

add_filter('redirect_canonical','my_disable_redirect_canonical');

function my_disable_redirect_canonical( $redirect_url ) {
    if ( is_singular( 'post' ) )
    $redirect_url = false;
    return $redirect_url;
}

ref: https://www.ads-software.com/support/topic/pagination-on-singlephp-causing-301-redirect?replies=10

Thank you very much for your suggestions, alchymyth.

But, that doesn’t work. Same link generated. I think I’m going to go to a newer theme.

Got the single page ‘newer’ and ‘older’ posts links working. Had to go back to the original single.php file without any of my modifications. ??

Thank you, again, alchymyth.