diff --git a/src/EnvReader/XmlStructure/AttributeSingleXmlStructure.php b/src/EnvReader/XmlStructure/AttributeSingleXmlStructure.php
index 4050289..2311624 100644
--- a/src/EnvReader/XmlStructure/AttributeSingleXmlStructure.php
+++ b/src/EnvReader/XmlStructure/AttributeSingleXmlStructure.php
@@ -26,6 +26,13 @@ class AttributeSingleXmlStructure implements IXmlStructure {
      * @inheritDoc
      */
     public function parseXml (SimpleXMLElement $xmlNode): string {
-        return (string)$xmlNode[$this->attributeName];
+        if (($attributes = $xmlNode->attributes()) !== null) {
+            foreach ($attributes as $attributeName => $attributeValue) {
+                if (mb_strtolower($attributeName) === mb_strtolower($this->attributeName)) {
+                    return (string)$attributeValue;
+                }
+            }
+        }
+        return '';
     }
 }
\ No newline at end of file