diff --git a/psalm.xml b/psalm.xml
index 83bb767..3c555d4 100644
--- a/psalm.xml
+++ b/psalm.xml
@@ -1,6 +1,6 @@
 <?xml version="1.0"?>
 <psalm
-    errorLevel="3"
+    errorLevel="8"
     resolveFromConfigFile="true"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xmlns="https://getpsalm.org/schema/config"
diff --git a/src/Config/Config.php b/src/Config/Config.php
index 5c509d3..7878b59 100644
--- a/src/Config/Config.php
+++ b/src/Config/Config.php
@@ -85,7 +85,7 @@ class Config implements ConfigInterface
 			case 'AWS_GIFT_CARD_PARTNER_ID':
 			case 'AWS_GIFT_CARD_ENDPOINT':
 			case 'AWS_GIFT_CARD_CURRENCY':
-				$return = $_ENV[$key] ?? '';
+				$return = (string)($_ENV[$key] ?? '');
 				break;
 			default:
 				break;