diff --git a/lib/yform/value/domain.php b/lib/yform/value/domain.php
index 0680749..0cd8a61 100644
--- a/lib/yform/value/domain.php
+++ b/lib/yform/value/domain.php
@@ -88,7 +88,7 @@ public static function getListValue(array $params): string
         $new_select = new self();
         $values = self::domains();
 
-        foreach (explode(',', $params['value']) as $k) {
+        foreach (explode(',', $params['value'] ??) as $k) {
             if (isset($values[$k])) {
                 $return[] = rex_i18n::translate($values[$k]);
             }