You could get the posts by slug instead of name. Like this:
$posts = get_posts(array(
'post_type' => 'coupon',
'numberposts' => -1,
'post_status' => array('publish', 'unreliable', 'draft'),
'tax_query' => array(
array(
'taxonomy' => 'stores',
'field' => 'slug',
'terms' => array( 'new-store' ),
'include_children' => false
)
)
));
Or you could get the posts by term id. like this:
$posts = get_posts(array(
'post_type' => 'coupon',
'numberposts' => -1,
'post_status' => array('publish', 'unreliable', 'draft'),
'tax_query' => array(
array(
'taxonomy' => 'stores',
'field' => 'term_id',
'terms' => array( 4 ),
'include_children' => false
)
)
));
Here you can find a guide on how to know the term id:
https://facetwp.com/how-to-find-a-wordpress-terms-id/