diff --git a/inc/class-sort.php b/inc/class-sort.php
index ac3fad3..8a72c77 100644
--- a/inc/class-sort.php
+++ b/inc/class-sort.php
@@ -300,13 +300,14 @@ final class Sort {
                     foreach ($wp_query->query['tax_query'] as $tax) {
                         if (!isset($tax['taxonomy'])) continue;
                         if ($current_relationship['taxonomy'] != $tax['taxonomy']) continue;
-                        $term_by = $tax['field'];
+                        $term_by = $tax['field'] ?? 'term_id';
                         $term_id = $tax['terms'];
                         break;
                     }
                 } else if ($current_relationship['taxonomy'] === 'category' && isset($wp_query->query['category_name'])) {
                     $term_id = $wp_query->query['category_name'];
                 }
+                if (is_array($term_id)) $term_id = array_values($term_id)[0];
                 if (empty($term_id)) return;
 
                 $term = get_term_by($term_by, $term_id, $current_relationship['taxonomy']);