Paginated Page end up with 404 in 2nd page

I have a paginated built in my theme. However, the pages linked, though the slugs are correct, give me 404 errors. I’ve tried everything, even changing the way pagination was achieved and flushing my rewrite rules several times.

Example:
https://quoteta.com/ works fine, while
https://quoteta.com/page/2/ gives a very not so welcome 404 error or a blank page.
Here is my codings :

<?php get_header(); ?>

<?php if (is_archive()) $post_number = get_option('dailynotes_archivenum_posts');
if (is_search()) $post_number = get_option('dailynotes_searchnum_posts');
if (is_tag()) $post_number = get_option('dailynotes_tagnum_posts');
if (is_category()) $post_number = get_option('dailynotes_catnum_posts');
if (is_home()) $args=array(
					   'showposts'=>get_option('dailynotes_homepage_posts'),
					   'paged'=>$paged,
					   'post_type' => array('note','photo','quote','video','customlink','audio','post')
					); ?>

<?php global $query_string;
if (is_category()) query_posts($query_string . "&showposts=$post_number&paged=$paged&cat=$cat");
elseif (is_home()) query_posts($args);
elseif (is_author()) {
	$qstring_array = array();
	parse_str($query_string,  $qstring_array);
	query_posts(array('showposts' => $post_number,'paged'=>$paged,'post_type' => array('note','photo','quote','video','customlink','audio'),'author'=>$qstring_array["author"])) ; }
else query_posts($query_string . "&showposts=$post_number&paged=$paged"); ?>

<?php
if (isset($_REQUEST["post_type"])) {
	$args=array(
	   'showposts'=> get_option('dailynotes_archive_customposts'),
	   'paged'=>$paged,
	   'post_type' => $_REQUEST["post_type"]
	);
	query_posts($args);
}; ?>

<div id="posts_big">
	<?php  $i = 0; if (have_posts()) : while (have_posts()) : the_post(); $i++; ?>
    <?php include(TEMPLATEPATH . '/includes/entry2.php'); ?>
    <?php endwhile; ?>
    <?php endif; wp_reset_query(); ?>
</div>	

<?php if (is_archive()) $post_number = get_option('dailynotes_archivenum_posts');
if (is_search()) $post_number = get_option('dailynotes_searchnum_posts');
if (is_tag()) $post_number = get_option('dailynotes_tagnum_posts');
if (is_category()) $post_number = get_option('dailynotes_catnum_posts');
if (is_home()) $args=array(
					   'showposts'=>get_option('dailynotes_homepage_posts'),
					   'paged'=>$paged,
					   'post_type' => array('note','photo','quote','video','customlink','audio','post')
					); ?>

<?php global $query_string;
if (is_category()) query_posts($query_string . "&showposts=$post_number&paged=$paged&cat=$cat");
elseif (is_home()) query_posts($args);
elseif (is_author()) {
	$qstring_array = array();
	parse_str($query_string,  $qstring_array);
	query_posts(array('showposts' => $post_number,'paged'=>$paged,'post_type' => array('note','photo','quote','video','customlink','audio'),'author'=>$qstring_array["author"])) ; }
else query_posts($query_string . "&showposts=$post_number&paged=$paged"); ?>

<?php
if (isset($_REQUEST["post_type"])) {
	$args=array(
	   'showposts'=> get_option('dailynotes_archive_customposts'),
	   'paged'=>$paged,
	   'post_type' => $_REQUEST["post_type"]
	);
	query_posts($args);
}; ?>
<?php global $default_colorscheme,$shortname;
$colorSchemePath = '';
$colorScheme = get_option($shortname . '_color_scheme');
if ($colorScheme <> $default_colorscheme) $colorSchemePath = strtolower($colorScheme) . '/'; ?>
<div id="posts">
	<?php next_posts_link('<img id="next2" src="'.get_bloginfo('stylesheet_directory').'/images/'.$colorSchemePath.'/'.'arrow.gif" alt="next page" />', 0); ?>
    <?php previous_posts_link('<img id="previous2" src="'.get_bloginfo('stylesheet_directory').'/images/'.$colorSchemePath.'/'.'previous.gif" alt="next page" />', 0); ?>

     <?php $i = 0; if (have_posts()) : while (have_posts()) : the_post(); $i++; ?>

        <?php include(TEMPLATEPATH . '/includes/entry.php'); ?>

    <?php endwhile; ?>

    <?php endif; wp_reset_query(); ?>	

	<div id="footer"><?php _e('Created by ','Sanjevi Rau'); ?> <a href="#">Sanjevi.R</a></div>
</div>			

<?php get_sidebar(); ?>

<?php get_footer(); ?>

Can anoyone find me a solution for this?